1. The document discusses various early attempts at classifying elements, including Dobereiner's classification of elements into triads based on their atomic masses and properties, Lavoisier's classification of elements as metals and non-metals, and Newlands' law of octaves. 2. Newlands noticed that when elements were arranged in order of increasing atomic mass, the eighth element had similar properties to the first element, analogous to the octave in music. This led to the idea of periodicity, where properties repeat at regular intervals. 3. The law of octaves was an important step towards recognizing a systematic relationship between the order of atomic masses and the periodic repetition of element properties, laying the foundation for

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CONCEPT FLOW CHART
Introduction
Necessity of classification
Early attempts
of classification
Mendleev’s
periodic table
Classification of elements
into blocks
Newlands law
of octaves
Long form
periodic table
Prediction of blocks
group and period
number of elements
Lavoisier classification
Achievements
Achievements
Defects
Defects
Dobereiner’s
classification
dechancourtois
classification

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Born at Hof in Bavaria, Johann Wolfgang
Dobereiner began as a pharmacist’s apprentice
in 1794, and later practised pharmacy at
Dillingburg, Karlsruhe and Strasbourg, where he
set up as a manufacturer of chemicals. For a time
he conducted and institute for teaching practical
chemistry ; then he joined a textile company and
set about improving dyeing processes. The
Napoleonic wars ruined him, but he was fortunate
to come to the notice of Goethe, who obtained
for him a professorship at Jena, where he
remained from 1810 until he died on March 24,
1849. Döbereiner is credited with improving and
giving a correct explanation of the making of
vinegar, but he is best known for directing
attention, in 1817, to the fact that the atomic
weight of strontium is the mean of those of Calcium and Barium. He also
noticed the same relationship with other ‘triads’ (Chlorine, Bromine, Iodine ;
Sulphur, Selenium, Tellurium).
PERIODIC CLASSIFICATION
J.W. DOBEREINER
1780 - 1849
Do You Know?
The only letter not in the periodic table is the letter ‘J’.

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PERIODIC CLASSIFICATION
Introduction:
Before the beginning of the eighteenth century when were only 30 elements
known, it was easier to study and remember their properties. In later years, when
number of elements discovered was increased, then it became difficult to study
them. So scientist felt the need of simple method to facilitate the study of the
properties of various elements and their compounds.
After numerous attempts they got success and elements were arranged in such a
manner that similar elements were grouped together and different elements were
separated. This arrangement of elements is known as classification of elements.
Which led to the formation of periodic table.
 How is it possible?
In library, the books are classified into various categories and sub-categories.
They are arranged on shelves accordingly. Therefore location of books becomes
easy.
Let us come back to chemistry. Most of the matter that we see, touch and feel is
made up of compounds. There are millions of such compounds existing presently.
You will be surprised to know that compounds are formed as a result of various
permutations and combination of only about 110 odd elements. To study properties
of these elements and their compounds is a tough task.
 How then was this task simplified?
This task was simplified by simple classification of elements into few groups.
Instead of studying each and every element or compounds, we just learn the
properties of groups.
The attempts were made by different scientists to classify elements based on
their properties.
 Necessity for Classification of Elements:
Following are the reasons for the classification of elements.
(a) The classification may help to study them better.
(b) The classification may lead to correlate the properties of the elements with
some fundamental property that is characteristic of all the elements.
(c) The classification may further reveal relationship between the different
elements.
 Early attempts for classification:
Greeks classification:
The ancient Greeks suggested that all matter consisted of four elements only -
Earth, air fire and water. But, their idea could not be supported by the experiments.

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 Classification on the Basis of Valency:
Realising the importance of valency in chemistry, an attempt was made to
classify elements on this basis.
The monovalent elements were classed together and
so were the divalent ones, the trivalent ones and so on.
However, such classification suffers from the following drawbacks.
1. Several elements have variable valency, e.g., Iron has a valency of 2 and 3,
Copper 1 and 2, Tin 2 and 4, Lead 2 and 4, etc. This makes the position of such
elements uncertain.
2. Such classification does not explain the diverse nature of elements having the
same valency. For example, both Sodium and Chlorine are monovalent, but they
are quite different from each other in chemical behaviour. Sodium is a strongly
electropositive metal whereas Chlorine is a strongly electronegative nonmetal.
Electropositive element – Easily donates an electron.
Electronegative element – Easily accepts an eleectron`
 Lavoisier’s classification - metals and non-metals:
By the late 1860’s, more than 60 chemical elements had been identified.
Based on similar physical and chemical properties, Lavoisier and early
chemists classified the elements into metals and non metals.
I) Elements which were malleable and ductile, good conductors of
heat and electricity and possessed characteristic metallic luster
were named as
ii) Elements which were brittle, bad conductors of heat and electricity
and did not possess metallic luster were named as
Certain elements such as antimony, arsenic, boron, silicon and
tellurium resembled metals in some respects and non metals in
certain respects and were therefore metalloids.
metals.
non-metals.
 Reasons for rejection of classification into Metals and Non-metals:
i) Some of the elements behave both as metals and non-metals.
ii) The elements were divided only into two broad categories which does not
help much in the study of elements.
 MAJOR CONTRIBUTIONS LEADING TO THE DEVELOPMENT OF MODERN
PERIODIC TABLE:
 Dobereiner’s triads
In the famous atomic theory of John Dalton (1805), it was suggested that the
atoms of an elements on the basis of their atomic masses.
In the year 1829, Johann Wolfgang Dobereiner, a German scientist was the first
to classify elements into groups based on John Dalton’s assertions. He grouped
the elements with similar chemical properties into clusters of three called
‘Triads’.

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The distinctive feature of a triad was the atomic mass of the middle element.
When elements were arranged in order of their increasing atomic masses, the
atomic mass of the middle elements was approximately the arithmetic mean of
the other two elements of the triad.
Examples of Dobereiner’s triad
Alkali metal
triad
Element
Lithium Sodium Potassium
Arithmetic
mean
Atomic
mass
7.0 23.0 39.0 23.0
Alkaline
Earth metal
triad
Element Calcium Strontium Barium
Arithmetic
mean
Atomic
mass
40.0 87.5 137 88.5
Halogen triad
Element Chlorine Bromine Iodine
Arithmetic
mean
Atomic
mass
35.5 80.0 127.0 81.25
 Defects of triad classification:
(i) A large number of similar elements could not be grouped into triads e.g., Iron,
Manganese, Nickel, Cobalt, Zinc and Copper are similar elements but could not be
placed in the triads.
(ii) It was possible that quite dissimilar elements could be grouped into triads
(iii) Dobereiner could only classify 3 triads successfully.
Since he failed to arrange the known elements in the form of triads, his attempt
at classification was not very successful.
 de chancourtois classification:
The next reported attempt was made by a French geologist, de Chancourtois in
1862. He arranged the known elements in order of increasing atomic weights and
proposed a cylindrical table of elements to display the periodic recurrence of
properties. He observed that the elements with similar properties arranged in a
vertical line form the centre of the spiral. However, this did not attract much
attention.
CUQ
1. Which of the following are correct reasons for the classification of elements?
1) The classification may further reveal relationship between the different
elements.
2) The classification may help to study them better.
3) To make the study of elements complicate.
4) Both 1 and 2

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2. The valency of Iron is:
1) 1 2) 6 3) 2 4) 0
3. Which of the following is the valency exhibited by Lead?
1) 2 2) 4 3) 3 4) Both 1 and 2
4. The atomic weight of Lithium is:
1) 4 2) 7 3) 5 4) 10
5. The law of Triads is applicable to:
1) Lithium, Beryllium, Boron 2) Fluorine, Chlorine, Bromine
3) Chlorine, Bromine, Iodine 4) Sodium, Potassium, Rubidium
6. Triads had greater significance in predicting the atomic mass and properties of
the ______ element.
1) First 2) Last 3) Middle 4) First and last
7. Which of the following elements could not grouped into triads even they are
similar?
1) Fe, Co, Ni 2) Li, Na, k 3) Ca, Sr, Ba 4) B, C, N
Single Correct Choice Type:
1. The law of triads was proposed by _________.
1) Dobereiner 2) Newlands 3) Lother Meyer 4) Chancourtois
2. The variable valency of Tin is:
1) 2 and 6 2) 1 and 3 3) 2 and 4 4) 1 and 2
3. Select the following pair of elements in which their arithmetic mean of atomic
weights is equal to the atomic weight of strontium.
1) Lithium, Barium 2) Sodium, Calcium
3) Calcium, Barium 4) Sodium, Barium
4. Identify the correct reasons for rejection of Lavoisier’s classification.
1) Some of the elements behave both as metals and non-metals.
2) Lavoisier classification does not help much in the study of elements.
3) Both 1 & 2
4) None of these

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5. Which of the following is the smallest in size?
1) Br 2) I–
3) I 4) Br –
6. Which of the following is an achievement of the triads classification?
1) Relation between all properties of all elements.
2) Relation between the atomic mass of all elements.
3) Relation between the properties of same elements.
4) Relation between only atomic weights of an element.
7. The Radioactive element which was discovered by Madam Curie and based on her
country name _________.
1) Uranium 2) Radium 3) Polonium 4) Neptunium
Multi Correct Choice Type:
8. Which of the following is / are correct statement (s)?
1) Sodium is a strongly electropositive metal.
2) Chlorine is a strongly electronegative metal.
3) Chlorine is a strongly electronegative non-metal.
4) Sodium is a strongly electropositive non-metal.
Statement Type:
9. Statement I: Classification of elements is not useful to reveal the relationship
between the different elements.
Statement II: Classification of elements may lead to correlate the properties of
the elements with some fundamental property that is characteristic of all the
elements.
1) Both statements I and II are correct.
2) Both statement I and II are incorrect.
3) Statement I is correct and statement II is incorrect.
4) Statement I is incorrect and statement II is correct.

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Comprehension Type:
Necessity for classification of elements
Following are the reasons for the classification of elements.
(1) The classification may help to study them better.
(2) The classification may lead to correlate the properties of the elements with
some fundamental property that is characteristic of all the elements.
(3) The classification may further reveal relationship between the different
elements
10. The elements which are malleable, ductile and good conductors of heat and
electricity are named as:
1) Non-metals 2) Metals 3) Metalloids 4) None of these
11. The elements which are brittle, bad conductors of heat and electricity are named
as:
1) Non-metals 2) Metals 3) Metalloids 4) None of these
12. The elements posses both metallic and non metallic characteristics are named
as:
1) Non-metals 2) Metals 3) Metalloids 4) None of these
Matrix Match Type:
13. Column-I Column-II
a) Lavoisier classified elements into p) Table of the relative weights of the
ultimate particles of gaseous and
other bodies
b) Dobernier classified q) 81.25
c) Dalton classification r) Metals and Non-metals
d) Mean atomic mass of s) Triads
Ca & Ba t) 88.5

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Integer Type:
14. Arithmetic mean of atomic weights of Li and K is ___________
Statement Type:
15. Statement I: Iron exhibits a variable valency.
Statement II: Chlorine is a mono-valent element.
1) Both statements I and II are correct.
2) Both statement I and II are incorrect.
3) Statement I is correct and statement II is incorrect.
4) Statement I is incorrect and statement II is correct.
Statement Type:
16. Dobereiner’s law is rejected due to :
Statement I: Quite large number of elements cannot be grouped into triads.
Statement II: It was possible to group quite dissimilar elements into triads.
1) Both statements I and II are correct.
2) Both statement I and II are incorrect.
3) Statement I is correct and statement II is incorrect.
4) Statement I is incorrect and statement II is correct.
17. G, O, D are the correct symbols of right elements of the periodic table arranged in
the increasing order of their atomic weights. The atomic weight of ‘G’ is 50 and
that of D is 138. If G, O, D are the elements of a Dobereiner triad, then find the
atomic weight of ‘O’.
1) 120.5 2) 98 3) 99.5 4) 77.5

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Newlands law of octaves:
John Alexander Reina Newland was a chemist as well as a lover of music.
Newland arranged many of the known elements in the increasing order of their
atomic masses. He started with the element having the lowest atomic mass
(hydrogen) and ended at thorium which was the 56th element.
He noticed that the eighth element was similar in properties to the first element,
just like the eighth note in music-Western as well as Indian.
The eighth element after Lithium is Sodium. In many of its chemical properties it
is similar to Lithium. Similarly, the eighth element after Sodium is Potassium,
whose properties are similar to Sodium. The eight element from Fluorine is
Chlorine both of which are similar in their properites. The eight element from
Nitrogen is Phosphorus and both these elements are similar in properties.
Western
Notes
Do Re Me Fa So La Ti
Sa Re Ga Ma Pa Da Ni
Indian
Notes
Hi Li Be B C N O
F Na Mg Al Si P s
Cl K Ca Cr Ti Mn Fe
Co and
Ni
Cu Zn Y In As Se
Br Rb Sr
Ce
and
La
Zr - -
Based on this observation, Newland stated his law of octaves that “When
elements are arranged in increasing order of their atomic mass, the eighth
element resembles the first in physical and chemical properties just like the
eighth one a musical scale resembles the first note”.
As a result, a very important conclusion was made that there is some systematic
relationship between the order of atomic masses and the repetition of properties
of elements.
This gave rise to a new term called “ periodicity ’’ which signified the
reoccurrence of characteristic properties of elements arranged in a table, at regular
intervals of a period.
 Achievements of the law of octaves:
 The law of octaves was the first logical attempt to classify elements based on the
of atomic weights.
 Periodicity of element was recognized for the first time.

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 Defects of law of octaves:
 The law could be best applied, only up to the element Calcium.
 Newly discovered elements could not fit into the octave structure.
 The feature of resemblance of the 8th element when arranged in increasing order
of their atomic mass was not successful with heavier elements.
 In order to fit element in to his table, Newland adjusted two elements in the same
column. For example, Cobalt and Nickel were placed in the same position and in
the same column as Fluorine, Chlorine and Bromine.
 Iron which resembles Cobalt and nickel in properties were placed for away from
these elements.
 No places were left for the known elements and so many elements occupied wrong
position that is why, the attempt was rejected.
CUQ
1. The law of octaves is given by:
1) Newland 2) Dobereiner
3) Lother Meyer 4) de Chancourtois
2. Name the scientist, who noticed that the eighth element was similar properties
of the first element is:
1) Newland 2) Dalton 3) Doberiener 4) Lother Mayer
3. Newland arranged the elements in:
1) Increasing order of Atomic number 2) Decreasing order of Atomic Number
3) Increasing order of Atomic Mass 4) Decreasing order of Atomic Mass
4. The systematic relationship between the order of atomic masses and the repetition
of properties of elements is called:
1) Atomicity 2) Periodicity 3) Nucleocity 4) Molecularity
5. In Newland’s law of octaves the eighth element after Beryllium is:
1) Magnesium 2) Bromine 3) Oxygen 4) Sulphur
6. In Newland’s law of octaves the eighth element after Carbon is:
1) Beryllium 2) Boron 3) Nitrogen 4) Silicon
7. In Newland’s table, the first element which shows similar properties with eighth
element is:
1) C, Al 2) Li, Na 3) O, P 4) H, F

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Single Correct Choice Type:
1. Law of octaves was proposed by:
1) O. Lother meyer 2) D.I. Mendeleev
3) J.W. Dobereines 4) J.A.R Newland
2. In Newland’s law of octaves the eighth element after Lithium is:
1) Sodium 2) Boron 3) Carbon 4) Beryllium
3. In Newland’s law of octaves the eighth element after Flourine is:
1) Chlorine 2) Bromine 3) Oxygen 4) Sulphur
4. Which of the following element properties are similar to the properties of
phosphorous?
1) Oxygen 2) Hydrogen 3) Nitrogen 4) Carbon
5. Which of the following pair has both members from the same period of the periodic
table?
1) Na - Ca 2) Na - Cl 3) Ca - Cl 4) Cl - Br
6. The electronic configuration of an element is 1s2
2s2
2p6
3s2
3p3
. The atomic number
of the element which is just below the above element in the periodic table is
___________.
1) 49 2) 31 3) 34 4) 33
7. Newland arranged the elements in:
1) Increasing order of atomic number. 2) Increasing order of atomic mass.
3) Decreasing order of atomic number. 4) Decreasing order of atomic mass.
8. The discovery of which of the following group of elements gave a death below to
the Newland’s law of octaves:
1) Inert gases 2) Alkaline earth metals
3) Rare earth metals 4) Actinides

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Multi Correct Choice Type:
9. Which of the following is correct statement?
1) Law of octaves could be best applied only upto the element Calcium.
2) Newly discovered elements could not fit into the octave structure.
3) Periodicity of element was recognised for the first time by Newland.
4) Law of octaves was based on atomic weights.
Statement Type:
10. Statement I: Nitrogen and Phosphorous exhibits similar chemical properties.
Statement II: Carbon and Silicon exhibits different chemical properties.
1) Both statements I and II are correct.
2) Both statement I and II are incorrect.
3) Statement I is correct and statement II is incorrect.
4) Statement I is incorrect and statement II is correct.
Comprehension Type:
John A. R. Newlands arranged the elements increasing order of the atomic weights,
the eighth element properties are similar to first element properties, similar to
the octave of music.
11. The law of octaves was proposed by J.A.R. Newlands is based on:
1) Atomic volume 2) Atomic number 3) Atomic weight 4) Mass number
12. Identify the correct achievement in Newlands classification of elements.
1) The law of octaves was the first logical attempt to classify elements on the
basis of atomic weights.
2) Periodicity of elements was recognised for the first time.
3) Newly discovered elements could fit into the octave structure.
4) Both 1 and 2
13. Identify the correct failures in Newlands classification of elements.
1) The law of octaves was the first logical attempt to classify elements on the
basis of atomic weights.
2) Periodicity of elements was recognised for the first time.
3) This law could be best applied, only up to the element Calcium.
4) All of these

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Matrix Match Type
14. Column-I Column-II
(Based on law of octaves)
a) The eighth element from Flourine is p) Phosphorus
b) The eighth element from Oxygen is q) Chlorine
c) The eighth element from Boron is r) Sulphur
d) The eighth element from Nitrogen is s) Aluminium
t) Calcium
Integer Type
15. The atomic mass of Chlorine is __________.
Multi Correct Choice Type:
16. According to Newland’s, which of the following elements having similar properties?
1) Lithium, Sodium and Potassium 2) Sodium, Chlorine, Bromine
3) Chlorine, Flourine 4) Potassium, Flourine
Statement Type:
17. Statement I: Newland arranged many of known elements in the increasing
order of their atomic weights.
Statement II: Newland laws of octave doesn’t applicable for heavier elements.
1) Both statements I and II are correct.
2) Both statement I and II are incorrect.
3) Statement I is correct and statement II is incorrect.
4) Statement I is incorrect and statement II is correct.

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Matrix Match Type:
18. Column-I Column-II
Element Atomic mass
a) Lithium p) 11
b) Beryllium q) 7
c) Boron r) 12
d) Carbon s) 9
t) 14
Mendeleev’s periodic table:
Dmitri Ivanovich Mendeleev, a Russian chemist was the first to make a very
significant contribution in the formation of periodic table. In 1860, there was a
conference of chemists in Karl Sruhe, Germany. A young Russian chemist, Dmitri
Mendeleev, attending this conference was deeply influenced by a thesis presented
by Stanislao Cannizaro, which decribed Cannizaro’s method of determining atomic
mass of elements. Mendeleev then started working on this aspect of atomic mass
and periodicity. He later on stated the law of chemical periodicity.
By chemical periodicity we mean that properties of the elements get repeated
after certain regular intervals.
In other words, Mendeleev’s Periodic law may also be stated as “When elements
are arranged in order of their increasing atomic masses, elements. This repeti-
tion of properties of elements after certain regular intervals is called periodic-
ity of properties.”
When Mendeleev started his work 63 elements were known as atomic masses
and oxides formed by the various elements were chosen as the basis of
classification of elements. While arranging the elements in groups and periods,
Mendeleev laid more stress on similar properties and made certain adjustments
in their atomic masses

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Groups
Periods 
Li
7
Na
23
K
39
Cu
63
Rb
85
Ag
108
Cs
133
Au
199
Be
9.4
Mg
24
Ca
40
Zn
65
Sr
87
Cd
112
Ba
137
Hg
200
F
19
C
35.5
l
Mn
55
Br
80
?
100
I
127
?
?
O
16
S
32
Cr
52
Se
78
Mo
96
Te
125
?
W
184
U
240
N
14
P
31
V
51
As
75
Nb
94
Sb
122
?
Ta
182
Bi
208
C
12
Si
28
Ti
48
?
72
Zr
90
Sn
118
Ce
140
La
180
Pb
207
Th
231
B
11
A
27.3
l
?
44
?
68
Yt
88
In
113
Di
138
Er
178
T
204
l
1
2
3
4
5
6
7
8
9
10
11
12
?
Fe
56
Co
59
Ni
59
Os
195
Ir
197
Pt
198
Ru
104
Rh
104
Pd
106
? ? ? ? ? ? ?
? ?
? ?
?
?
? ?
Characteristics of the periodic table:
Mendeleev arranged the elements in increasing order of their atomic masses in
horizontal rows in such a way that element with similar properties fall under
same vertical columns.
His periodic table consists of :
(i) Seven horizontal rows called periods.
(ii) Eight vertical columns called groups. These are designated as I, II, III, IV, V,
VI, VII, VIII. Except VIII group, each group is divided into two subgroups A
(Constituting representative elements) and B (constituting transition
elements). VIII groups contains 9 transition elements.

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Groups
1
2
3
4
5
6
7
H
1
Li
3
Na
11
K
19
Rb
37
Cs
55
Fr
87
Ca
20
Sr
38
Ba
56
Ra
88
Ga
31
In
49
T
81
l
Ge
32
Sn
50
Pb
82
As
33
Sb
51
Bi
83
Se
34
Te
52
Po
84
Br
35
I
53
At
85
Be
Be N
4
Mg
12
B
5
A
13
l
C
6
Si
14
7
P
15
O
8
S
16
H
1
F
9
C
17
l
He
2
Ne
10
Ar
18
Kr
36
Xe
54
Rn
86
Cu
29
Ag
47
Au
79
Zn
30
Cd
48
Hg
80
Sc
21
Y
39
Ti
22
Zr
40
Hf
72
V
23
Nb
41
Ta
73
Cr
24
Mo
42
W
74
Mn
25
Tc
43
Re
75
Fe
26
Ru
44
Os
76
Co
27
Rh
45
Ir
77
Ni
28
Pd
46
Pt
78
Lanthanide series *
(along with lanthanum)
Actinide series +
(along with actinium)
Ce
58
Th
90
Pr
59
Pa
91
Nd
60
U
92
Pm
61
Np
93
Sm
62
Pu
94
Eu
63
Am
95
Gd
64
Cm
96
Tb
65
Bk
97
Dy
66
Cf
98
Ho
67
Es
99
Er
68
Fm
100
Tm
69
Md
101
Yb
70
No
102
Lu
71
Lr
103
Achievements of Mendeleev’s periodic table:
1. Systematic study of the elements:
While developing the periodic table Mendeleev kept 2 things in mind.
(a) Increasing atomic masses.
(b) Grouping of similar elements together. This made the study of elements quite
systematic in the sense that if the properties of one element in a particular group
are known, those of the others can be predicted.
2. Prediction of new elements:
Mendeleev predicted the properties of some unknown elements and left gaps for
these elements the properties of future when they were discovered.
For example, Scandium, Gallium and Germanium were not known at that time
but Mendeleev already named these elements as Eka-boron, Eka-aluminium and
Eka-silicon. When these elements were later on discovered, they were found to
have more or less similar properties as predicted by Mendeleev.

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A comparative study of the properties of the elements predicted and later
discovered:
Property
Atomic weight
aluminium
Eka- Gallium
68 69.9
Specific gravity 5.9 5.94
Melting point Low 303.15°K
Formula of oxide Ea2O3 Ga2O3
Solubility in acid alkali Dissolves slowly in
both acid and alkali
Dissolves slowly in
both acid and alkali
Property
Atomic weight
Eka-silicon
Specific gravity
Melting point
Reaction with acid and
alkali
Dissolves neither by
hydrochloric acid nor
sodium hydroxide
72 69.9
5.5 5.47
High 958°C
Valency 4 4
Slightly attacked by
acids, resists attack
by alkali
Germanium
Property
Atomic weight
Oxide
Specific gravity
Sulphate
Scandium
44 43.79
Eb O
2 3
Eb (SO )
2 4 3
Sc O
2 3
Sc (SO )
2 4 3
3.5 3.864
3. Position of noble gases:
When noble gases were discovered they were placed in a new group without
disturbing the existing order.
4. Correction of atomic masses:
Atomic masses of several elements were corrected on the basis of periodic table.
For example, Atomic mass of Beryllium was corrected from 13.5 to 9.Mendeleev
predicted that atomic mass of Gold is incorrect. Later on it was found to be so.
Similarly, atomic masses of Indium, Uranium and Platinum were also corrected.
Drawbacks of Mendeleev’s periodic table:
1. Position of Hydrogen was uncertain:
It resembled IA group alkali metal elements and VII A(halogens) group elements.
2. Position of isotopes:
Isotopes of an element have similar chemical properties but different atomic masses.
Since basis of periodic table was increasing atomic mass. So, isotopes of
particular element should be placed separately.
3. Anomalous pairs of certain elements:
Certain elements were not arrange according to their increasing atomic mass.

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For example,
(a) Argon (Atomic mass 39.9) was placed before potassium (atomic mass 39.1)
(b) Cobalt (58.95) before Nickel (58.70)
(c) Tellurium (127.6) before Iodine (126.9)
(d) Thorium (232) before Protactimum (231)
4. Similar elements were placed in different group:
(a) Silver and Thallium
(b) Barium and Lead
(c) Copper and Mercury
(d) Platinum and Gold.
5. Dissimilar elements were placed in same group:
For example, Silver and Gold were placed in the same group while there is little
similarity in physical and chemical properties.
6. Cause of periodicity:
Mendeleev could not explain the cause of periodicity in the physical and chemical
properties of the elements.
Modern periodic table-Long form of the periodic table:
In the modern periodic table, elements are arranged in increasing order of their
atomic numbers. In such a way, the elements having the same number of valence
electrons are placed in the same vertical column.
It consists of 18 vertical columns and seven horizontal rows.
Vertical columns of periodic table are known as groups while horizontal rows are
known as periods.
The correlation between the groups in long form of periodic table and in modified
form of Mendeleev’s periodic table are given below.
CUQ
1. The elements having similar properties are repeated after certain definite intervals
are called:
1) Periodicity 2) Group 3) Atomic weight 4) Atomic number
2. The elements having similar properties are placed in the same vertical columns
is called:
1) Group 2) Period 3) Atomic number 4) Mass number
3. The number of elements known at that time when Mendeleev’s arranged in
the periodic table was _____________ number of elements.
1) 63 2) 60 3) 71 4) 65

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4. Eka –silicon is named as :
1) Titanium 2) Germanium 3) Scandium 4) Gallium
5. Which of the following elements position is not defined in Mendeleev’s periodic
table?
1) Oxygen 2) Helium 3) Chlorine 4) Hydrogen
6. Identify the anomalous pairs of elements from the following.
1) Ar and K 2) Co and Ni 3) Te and I 4) All of these
7. The most significant contribution towards the development of periodic table was
made by __________.
1) Mendeleev 2) Avagadro 3) Dalton 4)Cavendish
8. The physical and chemical properties of elements are the periodic function of
their atomic numbers, this was stated by __________.
1)Mendeleev 2) Lother Meyer 3) Moseley 4) Bohr
Single Correct Choice Type:
1. The most significant contribution towards the development of periodic table was
made by_______.
1) Mendeleev 2) Avagadro 3) Dalton 4) Cavendish
2. The number of groups present in Mendeleev’s periodic table is:
1) 8 2) 7 3) 9 4) 6
3. The horizontal rows and vertical columns of a periodic table are called ______ and
________ respectively. [ ]
1) Groups, periods 2) Periods, Groups
3) Blocks, partitions 4) Sections, segments
4. Which of the following pair is against to Mendeleev’s periodic laws?
1) Chromium, Manganese 2) Sodium, Magnesium
3) Copper, Zinc 4) Tellurium, Iodine
5. Mendeleev’s periodic table is based on:
1) Atomic weight 2) Atomic number 3) Atomic volume 4) All the above
6. What are the indefinite positions of Hydrogen element in Mendaleev’s periodic
table?
1) IB, IIIB 2) IA, IIB 3) IA, VIIB 4) VIIA, III B

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7. The number of elements in period 1 of the periodic table is:
1) 2 2) 8 3) 18 4) 32
8. According to Mendeleev’s periodic table transition elements are placed in:
1) VIII group 2) VII group 3) VI group 4) I group
9. The two places left empty by Mendeleev in the periodic table were for:
1) Aluminium and Silicon 2) Gallium and Germanium
3) Arsenic and Antimony 4) Antimony and Bismuth
Multi Correct Choice Type:
10. Which of the following is correct regarding Mendeleev’s periodic classification?
1) Similarities in the chemical properties of the elements.
2) Decreasing order of atomic weight of the elements.
3) Variation in the chemical properties of the elements.
4) Increasing order of atomic weights of the elements.
Statement Type:
11. Statement I: Lithium belongs IA group elements.
Statement-II: In Mendeleev’s periodic table except VIII group, every group is further
divided into sub-group.
1) Both statements I and II are correct.
2) Both statement I and II are incorrect.
3) Statement I is correct and statement II is incorrect.
4) Statement I is incorrect and statement II is correct.
Comprehension Type:
Mendeleev’s periodic table simplified the study of elements. It become useful in
studying and remembering the properties of a large number of elements, in a
simpler properties belonged to the same group. The physical and chemical properties
of the elements are the periodic functions of their atomic weight.
12. Which one of the following is the defect in Mendeleev’s periodic table:
1) The position of Hydrogen is not correctly defined.
2) In certain pairs of elements like Ar (40) and K (39), Co (58.9) and Ni (58.6);
Te (127.6) and I (126.9) and arrangement was not justified.
3) Mendeleev’s table was unable to explain the cause of periodicity among elements.
4) All the above.

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13. Which of the following element(s) atomic mass is corrected in Mendeleev’s periodic
classification of elements:
1) Indium 2) Gold 3) Platinum 4) All the above
14. According to Mendeleev’s periodic classification of elements
1) Eka-boron was named as scandium.
2) Eka-aluminium was named as Gallium
3) Eka-silicon was named as Germanium
4) All the above.
Matrix Match Type:
15. Column-I Column-II
a) Hydrogen p) 2nd period
b) Lithium q) 4th period
c) Sodium r) 1st period
d) Potassium s) 3rd period
t) 5th period
Integer Type:
16. Atomic weight of Gallium is __________.
Multi Correct Choice Type:
17. Mendeleev’s periodic table could not predict the following:
1) Isobars 2) Isotopes 3) Isotones 4) Atomic weight
Statement Type:
18. Statement I: In Mendeleev’s periodic table, the elements were arranged in vertical
columns, called groups.
Statement-II: The properties of element in same group and sub-group are different.
1) Both statements I and II are correct.
2) Both statement I and II are incorrect.
3) Statement I is correct and statement II is incorrect.
4) Statement I is incorrect and statement II is correct.
Statement Type:
19. Statement I: Atomic weight of Eka-boron is 44.
Statement-II: Atomic weight of Scandium is 43.79.
1) Both statements I and II are correct.
2) Both statement I and II are incorrect.
3) Statement I is correct and statement II is incorrect.
4) Statement I is incorrect and statement II is correct.
Multi Correct Choice Type:
20. Which of the following elements position cannot be justified on the basis of atomic
weight?
1) Rare earth elements 2) Alkali metals
3) Transition elements 4) Actinides

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Modern periodic law:
Moseley modified Mendeleev’s periodic law and proposed modern periodic law as
“The physical and chemical properties of the elements are periodic functions of
their atomic numbers.’’
Automatic Removal of Some Discrepancies in Mendeleev’s Periodic Table:
When the basis of arrangement is changed from atomic mass to atomic number,
the following discrepancies of Mendeleev’s periodic table automatically vanish.
 1. Position of isotopes:
All the isotopes of an element have the same atomic number, no matter what the
mass number is. Hence, the different isotopes of an element do not require separate
positions in the periodic table.
 2. Anomalous pairs of elements:
When arranged in increasing order of atomic number, (i) Ar(18) should precede
K(19), (ii) Co(27) should precede Ni(28) and, (iii) Te(52) should precede I(53). Thus
the positions of these elements stand justified and they no longer remain
anomalous pairs of elements.
Long form of the periodic table : (Characteristics of long form of periodic table):
A periodic table based on Bohr-Bury concept of electronic configuration and was
proposed by Rang, Werner, Bury and others and is known as Long Form of
Periodic Table or Bohr’s Table. It can be summarized as follows:
(1) It contains 7 periods (horizontal rows) and 18 groups (vertical columns).
(2) Each period starts with filling of electrons in new principal quantum number
and completes after the outermost shell is completely filled. The number of period
denotes the number of outermost shell of that element.
(3) It is studied in three portions.
 (a) The left portion: On the extreme left are groups 1 and 2, (i.e., IA and IIA
groups.) elements. These include alkali and alkaline earth metals or s-block
elements. These elements have strong electropositive character.
 (b) The right portion: On the extreme right are groups, 13, 14, 15, 16, 17, 18 (i.e.,
IIIA, lVA, VA, VIA, VIIA and zero group).Most of the elements are non-metals.
 (c) The middle portion: This portion is further divided into two parts:
 (i) Transition elements: This include ten groups, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 i.e.,
IIIB, IVB, VB, VIB, VIIB, VIII(8, 9, 10), IB and IIB sub-groups respectively.

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IV period 21Sc to 30Zn 3d series
V period 39Y to 48Cd 4d series
VI period 57La, 72Hf to 80Hg 5d series
VII period 89 104 105 112
Kurchatonium Hahnium Eka mercury
Ac, Ku , Ha, EKa 6d series
 (ii) Inner transition elements: These constitute two series:
(a) 58
Ce to 71
Lu : All 14 elements are placed just outside the table.
(b) 90
Th to 103
Lr : All 14 elements are placed just outside the table.
Description of Groups:
The salient features of groups are :
(i) There are 18 vertical columns in the periodic table which constitute 18 groups
or families. The groups are numbered as 1, 2, 3,... up to 18. All the members of a
particular group have similar outer shell electronic configuration.

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(ii) The elements of groups, 1, 2, 13, 14, 15, 16, 17 are known as representative
elements.
(iii) Except group 18 elements, elements from each group have their outermost
energy level (valence shell) incomplete while the inner energy levels (core shell)
are partially filled (d-block) or completely filled.
(iv) The elements of groups 1 and 2 have outer shell configuration as ns1
and ns2
,
respectively whereas those of groups 13, 14, 15, 16, 17, 18 possess ns2
np1
, ns2
np2
,
ns2
np3
, ns2
np4
, ns2
np5
and ns2
np6
configuration of valence shell, respectively.
(v) The elements of groups 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 possess ns1
or ns2
(ns0
also in some cases) in their valence shell with a core of ns1 to 2
,(n – 1)d1to10
. These
are known as Transition elements.
(vi) There are 14 elements just after Lanthanum (La: at.no. 57, group 3) and
another 14 elements just after Actinium (Ac : at.no. 89, group 3) which are placed
at the bottom of the main table. These are known as Lanthanides and Actinides,
respectively. These have the electronic configuration  
1to14 0or1 2
(n – 2)f n –1 d ns
NOTE
It is not necessary for all the elements in a particular
group to have similar electronic configuration e.g.,
In the following groups, abnormalities are observed.
gp. no 5 6 8 9 10
V Cr Fe CO Ni
3d 4s 3d 4s 3d 4s 3d 4s 3d 4s
Nb Mo Ru Rh Pd
4d 5s 4d 5s 4d 5s 4d 5s 4d
Ta W Os Ir Pt
5d 6s 5d 6s 5d 6s 5d 6s 5d 6s
23 24 26 27 28
41 42 44 45 46
73 74 76 77 78
3 2 5 1 6 2 7 2 8 2
4 1 5 1 7 1 8 1 10
3 2 4 2 6 2 7 2 9 1
Description of Periods:
The salient features of periods are :
(i) Seven horizontal rows of the periodic table are known as periods.
(ii) Each period begins with the outermost electron entering into a new principal
quantum number and completes after the outer­most shell’s p­subshell is complete.
(iii) The number of period denotes the number of outermost shell of that element.
(iv) The first element of each period (except 1 period) is an alkali metal and the
last element is an inert gas.
(v) The periods are described below :
1st
period very short period 2 element
2nd
and 3rd
periods short periods 8 elements
4th
and 5th
periods long periods 18 elements
6th
period very long period 32 elements
7th
period incomplete

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To avoid the inconvenience 14 elements, which do not include Lanthanum and
Actinium belonging to 6th
and 7th
period are placed in two separate rows at the
bottom of periodic table (now called as Lanthanoids and Actinoids respectively).
Note:
57
La and 89
Ac are d-block elements and should not be treated as Lanthanide and
actinide respectively but due to close resemblance in their properties with f-block
elements, they are studied with them.
Merits of the long form of periodic table:
We have seen that the periodic table has developed in various stages. The
classification evolving at every stage proved to be more useful than the previous
one. We will now discuss the uses of the periodic table.
Advantages of the Long Form of Periodic Table:
(i) This classification is based on the atomic number which is a more fundamental
property of the elements.
(ii) The position of elements in the periodic table is governed by the electronic
configurations, which determine their properties.
(iii) The completion of each period is more logical. In a period as the atomic
number increases, the energy shells are gradually filled up until an inert gas
configuration is reached.
(iv) It eliminates the even and odd series of IV, V and VI periods of Mendeleeff’s
periodic table.
(v) The position of VIII group is also justified in this table. All the transition
elements have been brought in the middle as the properties of transition elements
are intermediate between s- and p-block elements.
(vi) Due to separation of two sub-groups, dissimilar elements do not fall together.
One vertical column accommodates elements with same electronic configuration
thereby showing same properties.
(vii) The table completely separates metals and non-metals. Non-metals are present
in upper right corner of the periodic table.
(viii) There is a gradual change in properties of the elements with ‘ increase in
their atomic numbers i.e., periodicity of properties can be easily visualised. The
same properties occur after the intervals of 2, 8, 8, 18, 18 and 32 elements which
indicates the capacity of various periods of the table.
(ix) The greatest advantage of this periodic table is that this can be divided into
four blocks namely s, p, d and f-block elements.
(x) Since this classification is based on the atomic number and not on the atomic
mass, the position of placing isotopes at one place is fully justified.
(xi) It is easy to remember and reproduce.

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(xii) The position of some elements which were misfit on the basis of atomic mass
is now justified on the basis of atomic number. For example, Argon preceeds
Potassium because Argon has atomic number 18 and Potassium has 19.
(xiii) The lanthanoids and actinoids which have properties different from other
groups are placed separately at the bottom of the periodic table.
(xiv) This arrangement of elements is easy to remember and reproduce.
Anomalies of the Long Form of Periodic Table:
The long form of periodic table has removed all anomalies of the Mendeleevf’s
periodic table except:
(i) Position of H is not fixed till now.
(ii) Lanthanoids and Actinoids still find place in the bottom of the table.
(iii) It does not reflect the exact distribution of electrons among all the orbitals of
the atoms of all the elements.
Mendeleev’s
periodic Table
Modern Periodic
Table
1 Elements are
arranged. In the
increasing order
of their atomic
masses.
1 Elements are
arranged .In the
increasing order
of their atomic
numbers
2 There are a total
of 7
Groups (columns)
and 6 periods
(rows).
2 There are a total
of 18
Groups (columns)
and 7 periods
(rows).
3 The position of
Hydrogen could
not be explained.
3 Hydrogen is
placed
above alkali
metals
As it has one
valence electron.
4 No distinguishing
position for
metals and non-
metals was
assigned.
4 Metals are
present at the left
hand side of the
periodic table
whereas non-
metals are
present at the
right hand side.

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Common names of the elements:
Group
General or
Special Name
Reason
IA Alkali metals Due to the formation of strong oxides and
hydroxides with a strong Alkaline
character (Basic in nature), these are
called alkali metals.
IIA Alkaline earth
metals
These oxides are alkaline in nature and
exist in the earth. Hence, these elements
are called Alkaline Earth metals.
IIIA Boron family As all the elements in this group represent
similar properties and Boron being the
first of these elements, this group is called
the Boron group.
IVA Carbon family All the elements in this group have similar
properties. Carbon being the first element
of this group, this group is called the
Carbon group.
VA Pnicogens Pnicogen is a Greek word meaning
“suffocation”. As the Hydrides of this
group NH3, PH3, ASH3 have a pungent
odour, and when inhaled causes
suffocation, this group is called Pnicogen.
VIA Chalcogens Chalcogens in Greek means ore-forming.
Oxygen and sulphur are two important
elements of this group, and these elements
are associated with ores of many metals in
the form of their oxides and sulphides.
VII Halogens In Greek ‘halogen’ mean salt producer.
A salt consists of anion and cation. For
example common salt (NaCl) consists Na+
(cation) and Cl
(anion). The elements of
this group form the anion of salt easily,
hence they are called Halogens.
Zero
group
Rare gases
Inert gases
Noble gases
Because of their presence in small
quantities they are called rare gases. Due
to their stable electronic configuration they
are called as Noble gases. As they have
little tendency to react hence, they are also
called as Inert gases.
VIII or
VIIIB
Iron triad/
ferrous
metals/Platin
um
triads/Platinu
m metals
VIII group consists of 3 triad series. The
first triad series Fe, Co, Ni are called
ferrous metals and second and third triad
series Ru, Rh, Pd and Os, Ir, Pt are called
Platinum metals.
IB Coinage
metals
As these elements (copper group metals)
were used for the manufacture of
currencies in the olden days, they are
called Coinage metals.

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CUQ
1. As per the modern periodic law the physical and chemical properties of elements
are periodic functions of their________.
1) Atomic weight 2) Electronic configuration
3) Density 4) Atomic size
2. Long form of periodic table has :
1) 8 horizontal columns & 8 vertical rows
2) 7 horizontal rows & 18 vertical columns
3) 10 horizontal columns and 14 vertical rows
4) 14 horizontal columns and 10 vertical rows
3. Elements of IVB and III B are called :
1) Normal elements 2) Transition elements
3) Alkaline earth metals 4) Alkali metals.
4. Father of modern periodic table is ________.
1) mendeleev 2) Dober neir 3) Mosley 4) Newland
5. Which of the following group contains coinage metals :
1) IB 2) II B 3) III B 4) IV B
6. The electronic configuration of Rb :
1) 2s1
2) 3s1
3) (Ar) 4s1
4) (Kr) 5s1
7. The II A group elements are called :
1) Alkali metals 2) Alkaline earth metals
3) Transition metals 4) Inner transition metals
Single Correct Choice Type:
1. Which atomic number out of the following can not be accommodated in the present
setup of the long form of the periodic table ?
1) 112 2)118 3) 120 4) 116
2. The 3d-transition series contains elements having atomic numbers ranging from
________.
1) 22 to 30 2) 21 to 29 3) 21 to 31 4) 19 to 29
3. The starting element in the incomplete period of long form of periodic table
is________.
1) Cs 2) Rn 3) Fr 4) Th

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4. The longest period in the periodic table is ________.
1) 3rd
period 2) 6th
period 3) 7th
period 4) 5th
period
5. The 3rd
period of the periodic table contains:
1) 8 Elements 2) 32 Elements 3) 18 Elements 4) 19 Elements
6. The name of the element with atomic number 100 was adopted in honour of
1) Alfred Nobel 2) Enric Fermi
3) Dimitri Mendeleev 4) Albert Einstein
7. The long form of periodic table is nothing but just a graphical representation of
________principle
1) Pauli’s 2) Aufbau 3) Uncertainty 4) Wave mechanical
8. The atomic number of the element named after the scientist who introduced the
concepts of orbits or main energy levels :
1) 107 2) 108 3) 109 4) 110
9. Filling up of ‘f’ orbitals starts after with:
1) Actinium 2) Thorium 3) Ce 4) Lu
10. The 4th
period of the periodic table contains:
1) 8 Elements 2) 32 Elements 3) 18 Elements 4) 19 Elements
11. The period that contain only gaseous elements is ________.
1) period-1 2) period-2 3) period-4 4) period-7
12. In a period, elements are arranged in strict sequence of:
1) Decreasing charge in the nucleus. 2) Constant changes in the nucleus.
3) Equal charge in the nucleus. 4) Increasing charge in the nucleus.
Multi Correct Choice Type:
13. Group 18 (or zero group) elements are also called as:
1) Inert gases 2) Rare gases 3) Noble gases 4) Inactive gases

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Comprehension Type:
Different groups having are general or special names For example O group elements
general name is Rare gases inert gases or Noble gasses
14. General name of IA group elements is _______.
1) Alkaline earth metals 2) Alkali metals
3) Boron family 4) Carbon family
15. General name IIA group elements is ________.
1) Alkaline earth metals 2) Alkali metals
3) Boron family 4) Carbon family
16. General name IIIA group elements is ________.
1) Alkaline earth metals 2) Alkali metals
3) Boron family 4) Carbon family
Matrix Match Type:
17. Column-I Column-II
Period number Nature of period
a) 4 p) Very long period
b) 3 q) Long period
c) 2 r) Short period
d) 1 s) Very short period
t) Incomplete period
Multi Correct Choice Type:
18. Among the following elements having same general electronic configuration is
ns2
1) Ca 2) Sr 3) Be 4) Li
Statement Type:
19. Statement I : Atomic number is the number of protons in the nucleus of an atom.
Statement II : Atomic number is also equal to the number of electrons in a
neutral atom.
1) Both statement I and II are correct.
2) Both statement I and II are incorrect.
3) Statement I is correct and statement II is incorrect.
4) Statement I is incorrect and statement II is correct.
Multi Correct Choice Type:
20. Among the following elements which belongs to chalcogens ?
1) S 2) Se 3) Te 4) As

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Classification of elements into blocks:
This classification is based on the type of atomic orbital to which a differentiating
(last) electron enters. On the basis of electronic configuration, the elements are
grouped into four blocks. They are :
i) s-block elements ii) p-block elements iii) d-block elements iv) f-block elements
1,2
gp. 3
d - block
f - block
s
-
block
s -
block
p - block
Definition: The elements in which the last electron enters the s-subshell of their
outermost energy level are called s- block elements.
 (i) s - block:
(a) This block is situated at the extreme left of the periodic table.
(b) It contains elements of groups IA and IIA.
(c) The general electronic configuration of these elements is ns1-2
, where ‘n’
represents the outermost shell.
(d) The elements IA group elements are called Alkali metals and that of IIA group
elements are known as Alkaline earth metals.
(e) Li, Na, K, Rb, Cs, Fr elements have 1 electron in their outer shell with “ns1
”
general outer shell configuration, they belongs to IA (or) 1st
group.
(f) Be, Mg, Ca, Sr, Ba and Ra (Alkaline Earth elements) have 2-electrons in their
outer shell, with “ns2
” general outer shell configuration, they belongs to IIA (or)
2nd
group
 General characteristics of s-block elements are:
 They are soft metals and have low melting points.
 They are highly electropositive and have low ionisation energies .

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 They are highly reactive and form ionic compounds.
 They are good reducing agents.
 (ii) p - block:
Definition: The elements in which the last electron enters the p-subshell of
their outermost energy level are called p- block elements.
(a) This block is situated at the extreme right side of the periodic table.
(b) It contains elements of groups IIIA, IVA, VA, VIA, VIIA and VIIIA (exception-
Helium).
(c) The general electronic configuration of these elements is ns2
np1-6
, where ‘n’
represents the outermost shell.
(d) It includes metals, non metals , metalloids and inert gases.
 Remember:
a) Infact Helium belongs to s-block, but keeping its chemical inertness, Helium
is placed along with other inert gases in 0-group.
b) Hence He is a p-block element with out p-electrons.
c) The first p-block element is Boron [(He) 2s2
2p1
]
d) The only group with all gaseous elements is “0-group” and the any period with
all gaseous elements is 1st
.
 General characteristics of p-block elements are:
 They form ionic as well as covalent compounds.
 They have relatively high values of ionisation energies.
 Most of them are non metals and are highly electronegative.
 They show variable oxidation states and form acidic oxides.
 (iii) d - block:
Definition: The elements in which the last electron enters the d-subshell of the
penultimate energy level are called d- block elements.
(a) This block is situated in between ‘s’ and ‘p’ blocks of the periodic table.
(b) It contains elements of groups IB, IIB, IIIB, IVB, VB, VIB, VIIB and VIII groups.
(c) The general electronic configuration of these elements is ns1-2
(n–1)d1–10
,
where (n-1) represents the penultimate shell and ‘n’ represents the outermost
shell.
(d) It includes weak metals.
d - block elements are further classified into following transition series on the
basis of which (n-1)d is being filled.

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1) 3d series - electronic configuration.
4s1-2
3d1-10
[Sc(Z=21) to Zn (Z=30)]
2) 4d - series - electronic configuration.
5s1-2
4d1-10
[Y(Z=39) to Cd (Z=48)].
3) 5d- series - electronic configuration.
6s1-2
5d1-10
.[La (Z=57), Hf (Z=72) to Hg (Z=80)]
4) 6d - series - is an incomplete series.
 General characteristics of d-block elements are:
 They are hard, high melting metals showing variable oxidation states.
 They form coloured complexes and form ionic as well as covalent compounds.
 Most of them exhibit paramagnetism and possess catalytic properties.
 They form alloys and are good conductors of heat and electricity.
 (iv) f - block:
Definition: The elements in which the last electron enters the f-subshell of the
anti-penultimate (third to the outer most shell ) shell are called f- block elements.
(a) This block is placed separately at the bottom of the main periodic table.
(b) It consists of two series of elements placed at the bottom of the periodic table.
The elements of first series follow lanthanum and are called Lanthanides and
the elements of second series follow actinium and are called actinides.
(c) The general electronic configuration of these elements is (n-2)f1-14
(n-1) d 0-1
ns2
, where ‘n’ represents the outermost shell, (n-1) represents the penultimate
shell and (n - 2) represents the anti penultimate shell.
 General characteristics of f-block elements are:
 They are hard and have high melting metals showing variable oxidation states.
 They form coloured complexes and have high densities.
CUQ
1. On the bases of electronic configuration, the elements are grouped in to _______
blocks.
1) 2 2) 4 3) 1 4) 3
2. The elements in which the last electron enters the s-subshell of their outermost
energy leve are called :
1) s-block 2) p–block 3) d–block 4) f–block

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3. The elements in which the last electron enters the p-subshell of their outermost
energy level are called :
1) s-block 2) p–block 3) d–block 4) f–block
4. The elements in which the last electron enters the d-subshell of their outermost
energy level are called :
1) s-block 2) p–block 3) d–block 4) f–block
5. The elements in which the last electron enters the f-subshell of their outermost
energy level are called :
1) p-block 2) s–block 3) f–block 4) d–block
6. s–block contains ––––––––– groups.
1) I B & II B 2) I A & IIA 3) IIIA & IV A 4) Only I A
7. The II A group elements are called:
1) Alkali metals 2) Alkaline earth metals
3) Transition metals 4) Inner transition metals
8. The atomicity of a noble gas is:
1) 2 2) 1 3) 4 4) 6
9. f–block elements are called :
1) Normal elements 2) Representative elements
3) Transition elements 4) Inner transition elements
10. The elements which are characterised by the outer shell electronic configuration
from ns1
to ns2
np5
are collectively called as:
1) Transition elements 2) Inner transition elements
3) Representative elements 4) Actinides
Single Correct Choice Type:
1. The elements whose outer electronic configuration vary from ns2
np1
to ns2
np6
constitute?
1) s-Block of elements 2) p-Block of elements
3) d-Block of elements 4) f-Block ol elements
2. Elements which generally exhibit variable oxidation states and form coloured
ions are:
1) Metalloids 2) Transition elements
3) Non-metals 4) Gases
3. Lanthanides are group of elements in which the differentiating electron enters
into __________.
1) s-sublevel 2) d-sublevel 3) p-sublevel 4) f-sublevel

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4. The atomic numbers of Lanthanides are from __________.
1) 58 to 71 2) 90 to 103 3) 21 to 30 4) 39 to 48
5. In the long form of periodic table all non-metals are placed in__________.
1) s - block 2) p - block 3) d - block 4) f - block
6. Lanthanum belongs to ...... group.
1) III B 2) II B 3) IV B 4) II A
7. In the long form of periodic table inert gases are _________ group.
1) 15 2) 16 3) 18 4)19
8. The last lanthanide is:
1) La 2) Ce 3) Th 4) Lu
9. Elements with atomic numbers 9, 17, 35, 53 are collectively known as:
1) Chalcogens 2) Halogens 3) Lanthanides 4) Rare gases
10. In iron atom (z=26), the differentiating electron enters……..sublevel.
1) 4d 2) 3d 3) 4p 4) 5p
11. Ce — 58 is a member of :
1) s - block 2) p - block 3) d - block 4) f - block
12. In the transition elements, the incoming electron occupies (n–1)d sub level in
preference to__________.
1) np 2) ns 3) (n–1)d 4) (n+1)s
13. The element with the electronic configuration [Xe]4f7
5d1
6s2
lies in the:
1) s-Block 2) d-Block 3) f-Block 4) p-Block
14. The fourteen elements collectively placed in group 3 (or IIIB) and 7th
period are
called:
1) d-Block elements 2) p-Block elements
3) s-Block elements 4) Actinides
15. Atoms with three of their outer most orbits incompletely filled with electrons are
present in __________.
1) Lanthanides 2) Representative elements
3) s - block elements 4) Transitional elements

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16. First transitional series is present in __________.
1) Third period 2) Fifth period 3) Fourth period 4) Sixth period
Multi Correct Choice Type:
17. The atomic number of the following represents the element in the d-block?
1) Z= 40 2) Z = 74 3) Z = 45 4) Z = 49
Comprehension Type:
This classification is based on the type of atomic orbital to which a differentiating
(last) electron enters. On the bases of electronic configuration, the elements are
grouped into four blocks. They are :
i) s-block elements ii) p-block elements
iii) d-block elements iv) f-block elements
18. Which of the following is/are the characterstics of the s - block elements?
1) Highly electro positive 2) Non - metallic
3) Acidic nature 4) All the above
19. Which of the following is/are the characterstics of the p - block elements?
1) Highly electro negative 2) Metals
3) Highly malleable 4) All the above
20. The elements whose atoms have outer most and penultimate shells incomplete
are called:
1) s-Block elements 2) p-Block elements
3) d-Block elements 4) f-Block elements
Matrix Match Type:
21. Column-I Column-II
a) First transition series p) Incomplete series
b) Second transition series q) 5d1-9
6s1-2
c) Third transition series r) 4d1-9
5s1-2
d) Fourth transition series s) 3d1-9
4s1-2
t) 6d series
Integer type:
22. How many groups are occupied by p-block elements in long form of periodic table?

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Multi Correct Choice Type:
23. Which of the following are correct statements for d-block elements?
1) 3d series electronic configuration is 3d1-10
4s1-2
2) 4d - series electronic configuration is 4d1-10
5s1-2
3) 5d - series electronic configuration is 5d1-10
6s1-2
.
4) All d–block elements diamagnetic
Multi Correct Choice Type:
24. Identify the characterstics of d - block elements:
1) Variable Oxidation states 2) Forms alloys
3) Formed coloured complexes 4) Bad conductors
Prediction of block, group, period of an element based on electronic
configuration
i. Prediction of block
If differentiating electron enters into
a) s-subshell  s-block
b) p-subshell  p-block
c) d-subshell  d-block
d) f-subshell  f-block
ii. Prediction of period
Maximum value of principal quantum number in the given electronic configuration
of an element indicates the period of that particular element
Example: Scandium- 2 2 6 2 6 2 1
1 2 2 3 3 4 3
s s p s p s d
Here maximum principal quantum number = 4
Hence period = 4
iii. Prediction of group
For s-block elements
Group number = No of valence electrons
Example: Calcium- 2 2 6 2 6 2
1 2 2 3 3 4
s s p s p s

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Here No of valence electrons = 2
Hence, group number of Calcium = 2
For p-block elementts:
Group number = 10+ no of valence electrons
Example: Phosphrous- 2 2 6 2 3
1 2 2 3 3
s s p s p
Here No of valence electrons = 5
Hence, group number of phosphorous = 10+5 = 15
For d-block elements;
Group number = no of valence electrons+No of electrons in (n-1)d subshell.
Example: Titanium- 2 2 6 2 6 2 2
1 2 2 3 3 4 3
s s p s p s d
Here No of valence electrons =
2
2 4s
 
 

No of electrons in (n-1)d subshell =
2
2 3d
 
 

Hence, group number of Titanium = 2+2 = 4
Note:
1. Group number of f-block elements is always 3.
2. Group numbers are alloted on the basis of arabic numbers (1, 2, 3, 4, .......,18)
Electronic configuration of s-block elements:
Element At.no. Electronic configuration
LI 3   1
2
He s
Na 11   1
3
Ne s
K 19   1
4
Ar s
Rb 37   1
5
Kr s
Cs 55   1
6
Xe s
Fr 87   1
7
Rn s (Radioactive)
Electronic configuration of p-block elements:
Electronic configuration Group Number
2 1
ns np 13 (IIIA)
2 2
ns np 14 (IVA)
2 3
ns np 15 (VA)
2 4
ns np 16 (VIA)
2 5
ns np 17 (VIIA)
2 6
ns np 18 (Zero group or VIIIA)

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Electronic configuration of d-block elements:
Electronic configuration Group Number
 
2 1
1
ns n d
 3 (IIIB)
 
2 2
1
ns n d
 4 (IVB)
 
2 3
1
ns n d
 5 (VB)
 
1 5
1
ns n d
 6 (VIB)
 
2 5
1
ns n d
 7 (VIIB)
 
2 6
1
ns n d
 8 (VIIIB)
 
2 7
1
ns n d
 9 (VIIIB)
 
2 8
1
ns n d
 10 (VIIIB)
 
1 10
1
ns n d
 11 (IB)
 
2 10
1
ns n d
 12 (IIB)
Electronic configuration of f-block elements:
     
     
1 14 0(or)1 2
1 14 0(or)1 2
4f n 2 f n 1 d ns n 6
5f n 2 f n 1 d ns n 7


   
   
CUQ
1. The element with Z = 10 belongs to :
1) 1st
period 2) 2nd
period 3) 7th
period 4) 6th
period
2. The element with atomic number 19 is__________.
1) Halogen 2) Chalcogen 3) Noble gas 4) An alkali metal
3. The general electronic configuration of s-block elements is __________.
1) ns1-2
2) ns2
np1-6
3) 3d1to10
4) ns1-3
4. s–block contains ––––––––– groups.
1) I B & II B 2) I A & IIA 3) IIIA & IV A 4) Only I A
5. The general electronic configuration of p-block elements is __________.
1) ns1-2
2) ns2
np1-6
3) 3d1to10
4) ns1-3

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Single Correct Choice Type:
1. What is the atomic number of Darmstadtium ?
1) 109 2) 108 3) 110 4) 111
2. The electronic configuration of an element ‘M’ is [Ar] 3d10
4s2
4p3
. Then ‘M’ belongs
to __________.
1) VB group 2) VIII group 3) VA group 4) 0 group
3. The element with atomic number 17 is __________.
1) Cl 2) Ar 3) Br 4) F
4. Titanium & Ca belong to the ____________Period.
1) 3rd
period 2) 4th
period 3) 2rd
period 4) 7th
period
5. Among the following, the element with the atomic number 23 is__________.
1) Ca 2) K 3) Pt 4) V
6. The element with the electronic configuration [Xe]4f7
5d1
6s2
lies in the:
1) s-Block 2) d-Block 3) f-Block 4) Actinide series
7. The atomicity of a noble gas is __________.
1) 2 2) 1 3) 4 4) 6
8. The fourteen elements collectively placed in group 3 (or IIIB) and 7th
period are
called:
1) d-Block elements 2) p-Block elements
3) s-Block elements 4) Actinides
9. Which of the following is not the electronic configuration of a representative
element?
1) ns2
2) ns2
np5
3) ns2
np1
4) ns2
np6
10. In the long form of periodic table all non-metals are placed in __________.
1) s - block 2) p - block 3) d - block 4) f - block
11. First transitional series is present in_________.
1) Third period 2) Fifth period 3) Fourth period 4) Sixth period

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12. Element with atomic numbers 9 belongs to __________period.
1) Second period 2) Fourth period 3)Fifth period 4) Sixth period
13. Lanthanum belongs to ______group.
1) III B 2) II B 3) IV B 4) II A
14. In the long form of periodic table inert gases are _________group.
1) 15 2) 16 3) 18 4)19
Multi Correct Choice Type:
15. Sodium Atomic number is 11, identify group & period number are _______.
1) 1 2) 3 3) 4 4) 5
16. Identify the correct statesments from the following:
1) Magnesium belongs to Second group.
2) Magnesium belongs to Third period.
3) Magnesium atomic number is 12.
4) Magnesium is d - block element
Comprehension Type:
The differentiating electron enters into d - subshell are called d - block elements
17. Which of the following represents the electronic configuration of d-block elements?
1) (n-1)s2
nd1-10
2) (n-1)d1-10
ns1-2
3) (n-1)s2
p6
, ns1
4) ns2
p2
d1
18. The general electronic configuration (n-1) d3
ns2
indicates that particular element
belongs to __________.
1) VB 2) IVB 3) VIB 4) IIIB

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19. The atomic number of the following represents the element in the p - block:
1) Z = 7 2) Z = 9 3) Z = 10 4) All of these
Matrix Match Type:
20. Column - I Column - II
Element Blocks
a) Na p) s-block
b) N q) p-block
c) Ce r) d-block
d) Sc s) f-block
Multi Correct Choice Type:
21. Which of the following elements belongs to same group?
1) F 2) Cl 3) I 4) Br
22. Which of the following elements belongs to same period?
1) K 2) Ca 3) S 4) F
Matrix Match Type:
23. Column-I Column-II
Elements Period number
a) F p) 1
b) S q) 3
c) H r) 2
d) He s) 4

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PERIODIC CLASSIFICATION
KEY & SOLUTIONS
WORKSHEET -1 KEY
CUQ:
1) 4 2) 3 3) 4 4) 2
5) 3 6) 3 7) 1
JEE MAIN AND ADVANCED:
1) 1 2) 3 3) 3 4) 3
5) 1 6) 4 7) 3 8) 1,3
9) 4 10) 2 11) 1 12) 3
13) a-r;b-s;c-p;d-t 14) 23.0 15) 1 16) 1
17) 2
WORKSHEET -2 KEY
CUQ:
1) 1 2) 1 3) 3 4) 2
5) 1 6) 4 7) 2
JEE MAIN AND ADVANCED:
1) 4 2) 1 3) 1 4) 3
5) 2 6) 4 7) 2 8) 1
9) 1,2,3,4 10) 3 11) 3 12) 4 13) 3
14) a-q; b-r; c-s; d-p 15) 35.5 16) 1,3 17) 1
18) a-q; b-s; c-p; d-r
WORKSHEET -3 KEY
CUQ:
1) 1 2) 1 3) 1 4) 2
5) 4 6) 4 7) 1 8) 3
JEE MAIN AND ADVANCED:
1) 1 2) 1 3) 2 4) 4
5) 1 6) 3 7) 1 8) 1
9) 2 10) 1,4 11) 1 12) 4
13) 4 14) 4 15) a-r; b-p; c-s; d-q 16) 69.9
17)1,2,3 18) 3 19) 1 20) 1,4
WORKSHEET -4 KEY
CUQ:
1) 2 2) 2 3) 2 4) 3
5) 1 6) 4 7) 2

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JEE MAIN AND ADVANCED:
1) 3 2) 2 3) 3 4) 2
5) 1 6) 2 7) 2 8) 1
9) 3 10) 3 11) 1 12) 4
13) 1,2,3,4 14) 2 15) 1 16) 3
17) a - q, b -r, c -r, d -s 18) 1,2,3,4 19) 1
20) 1,2,3
WORKSHEET -5 KEY
CUQ:
1) 2 2) 1 3) 2 4) 3
5) 3 6) 2 7) 2 8) 2
9) 4 10) 3
JEE MAIN AND ADVANCED:
1) 2 2) 2 3) 4 4) 1
5) 2 6) 1 7) 3 8) 4
9) 2 10) 2 11) 4 12) 2
13) 3 14) 4 15) 1 16) 3
17) 1,2,3 18) 1 19) 1 20) 3
21) a-s; b-r; c-q; d-p, t 22) 6 23) 1,2,3
24) 1,2,3
WORKSHEET -6 KEY
CUQ:
1) 2 2) 4 3) 1 4) 2
5) 2
JEE MAIN AND ADVANCED:
1) 2 2) 1 3) 1 4) 2
5) 4 6) 4 7) 2 8) 4
9) 4 10) 2 11) 3 12) 1
13) 1 14) 3 15) 1, 2 16) 1,2,3
17) 2 18) 1 19) 4
20) a - p, b -q, c -s, d -r 21) 1,2,3,4 22) 1,2
23) a -r; b -q; c -p; d -p