CLASSIFICATION OF ELEMENTS,Periodic Table,NEED OF CLASSIFICATION,The Modern Periodic Table and many more....

1. BY
COMPUTER
CAREERS

2. “It is defined as the table in which all the
elements are arranged in the order of
increasing atomic numbers.”
In other words, it classifies all the known
elements according to their properties so
that the elements with similar properties are
placed together in same group while with
different properties are separated from each
other.

3.  1. To study the elements in a
better way
 2. To correlate the properties
of the elements.
 3. To study relationship
between different elements.
3

4. Four main groups:
1. Main group elements - elements having
outer shells consisting solely of s and p
electrons (s and p block elements)
2. Transition metals – first, second and
third transition series. ( d block)
3. Lanthanides – 4f orbitals being filled
4. Actinides – 5f orbitals being filled
Lanthanides and Actinides = f block
elements

6. The main group elements (also called the representative elements)
are the elements in Groups 1A through 7A.

7. The noble gases are found in Group 8A and have completely
filled p subshells.

8. The transition metals are found in Group 1B and 3B through 8B.
Group 2B have filled d subshells and are not transition metals.

9. The lanthanides and actinides make up the f-block transition
elements.

10. There is a distinct pattern to the electron
configurations of the elements in a particular group.
For Group 1A: [noble gas]ns1 For Group 2A: [noble gas]ns2

11.  A block of the periodic table of elements is a set of
adjacent groups.
 The respective highest-energy electrons in each
element in a block belong to the same atomic
orbital type.
 Each block is named after its characteristic orbital.
thus, the blocks are:
s-block
p-block
d-block
f-block
g-block (hypothetical)
LET US UNDERSTAND ABOUT EACH BLOCK - -

12. The S-block is a block in the
periodic table that consists of the
first two groups.
The elements in the s-block
generally exhibit well-defined
trends in their physical and
chemical properties, changing
steadily moving down the groups.
Their properties can be most
readily explained in terms of
their electron configuration, with
their valence electrons occupying s-
orbitals.

13. P BLOCK

14. The p-block of the periodic table of
the elements consists of the last six groups except
helium (which is located in the s-block).
In the elemental form of the p-block elements, the
highest energy electron occupies a p-orbital.
The p-block contains all of the nonmetals (except
for hydrogen and helium, which are in the s-block)
and semimetals, as well as the post-transition metals.
The groups of the p-block are:
(IIIB, IIIA): Boron group
14 (IVB, IVA): Carbon group
15 (VB, VA): Nitrogen group (or pnictogens)
16 (VIB, VIA): Chalcogens
17 (VIIB, VIIA): Halogens
18 (Group 0): Noble gases (excluding helium)

15. The d-block is the block or portion of
the periodic table that contains the element
groups 3–12.
These groups correspond to the filling of
the atomic d-orbital sub shell of the second
outermost shell with electron configurations
ranging from s2d1 (Group 3) to s2d10 (Group
12).
The d-block elements are often also known
as transition metals or transition elements
However the exact limits of the transition
metal region are usually not considered to be
identical to the d-block.
There are some irregularities in the
sequence; for example Cr is s1d5 (not s2d4)
and the Group 11 metals are s1d10(not s2d9),
so that the d-subshell is actually complete at
Group 11.

16. The f-block of the periodic table of
the elements consists of those elements whose atoms or
ions have valence electrons in f-orbitals.
Actual electronic configurations may be slightly
different from what is predicted by the Aufbau principle.
The elements are also known as inner transition
elements, although that term is normally taken to
include lutetium and lawrencium as well, which are part
of the d-block.

17. There are currently seven periods in the periodic table of chemical
elements, culminating with atomic number 118.
If further elements with higher atomic numbers than this are discovered,
they will be placed in additional periods, laid out to illustrate periodically
recurring trends in the properties of the elements concerned.
No elements in this region have been synthesized or discovered in
nature.
The first element of the g-block may have atomic number121, and thus
would have the systematic name unbiunium.
Elements in this region are likely to be highly unstable with respect to
radioactive decay, and have extremely short half lives, although element
126 is hypothesized to be within an island of stability that is resistant to
fission but not to alpha decay.
According to the orbital approximation in quantum
mechanical descriptions of atomic structure, the g-block would
correspond to elements with partially filled g-orbitals. However, spin-
orbit coupling effects reduce the validity of the orbital approximation
substantially for elements of high atomic number.

18.  Inert gases are gases that belong to Group VIII at the periodic table and its
distinct characteristic is that they will hardly react and even do not react at all
with other chemical such as metal or acid.
 These undesirable chemical reactions are
often oxidation and hydrolysis reactions with the oxygen and moisture in air.
Purified nitrogen and argon gases are most commonly used as inert gases due
to their high natural abundance (78% N2, 1% Ar in air) and low relative cost.
Inert gas is produced on board crude oil carriers (above 20,000 tonnes) by
using either a flue gas system or by burning kerosene in a dedicated inert gas
generator.
The costs of inert gases are directly related to how difficult it is to extract
them from the air.
NOW LET US KNOW INERT GASES IN DETAIL : -

19. Name Symbol Atomic Boiling Max. Avail. Amt.
in the Number Point(C) Pressure (PSI) Atmosphere US$/ltr.
Helium He 2 -268.9 6,000 5.2 PPM $ .10
Neon Ne 10 -246.07 6,000 18.2 PPM $ 1.00
Argon Ar 18 -185.88 6,000 7600 PPM $ .10
Krypton Kr 36 -156.6 1,350 1.1 PPM $ 3.00
Xenon Xe 54 -108.06 800 0.036 PPM $11.00
INERT GASES

20. REPRESENTATIVE OR MAIN GROUP ELEMENTS

21. The representative elements are all the elements in groups
one, two, thirteen, fourteen, fifteen, sixteen, seventeen and
eighteen of the periodic table.
The representative elements in the periodic table do not exhibit
variable valencies.
These include metals, non metals and semi metals (metalloid).
The metals are present in the left groups of the representative
elements, while the non metals are present in the right most groups and
the semi metals (metalloid) are present in the middle in a the shape of a
zig zag line that separates the metals from the non metals.
These elements are also called the main group elements of the
periodic table.

22. There are a total of 44 elements in representative
elements.
These include the Alkali metals, the Alkaline earth metals,
theHalogens, the Nitrogen family, the Carbon family of
elements, the Oxygen family of elements, the Boron
family of elements and the noble gases present at the far
right group.
The main group elements form the S and P blocks of the
periodic table.
These elements are the most abundant elements on the
earth.

23. An atomic orbital is a mathematical function that describes the wave-like
behavior of either one electron or a pair of electrons in an atom.
Atomic orbitals are the basic building blocks of the atomic orbital model, a
modern framework for visualizing the submicroscopic behavior of electrons in
matter.
In this model the electron cloud of a multi-electron atom may be seen as
being built up in an electron configuration that is a product of simpler
hydrogen-like atomic orbitals.
The repeating periodicity of the blocks of 2, 6, 10, and 14 elements within
sections of the periodic table arises naturally from the total number of electrons
which occupy a complete set of s, p, d and f atomic orbitals, respectively.

24. The atomic orbitals differ in shape.
That is, the electrons they describe have different probability
distributions around the nucleus.
Indeed, a part of the reason why orbitals differ in energy is
that the electrons that occupy them are likely to be found in
different regions around the parent nucleus and hence
experience the latter's attraction with different strengths.
The fact that all orbitals of a given shell in the hydrogen atom
have the same energy despite having different shapes is
surprising and is associated with a cancellation of different
contributions to the energy.
The possession of the same energy by different wavefunctions,
is also associated with the coincidental numerical agreement of
Bohr's model with experiment
Let us know about about Orbitals : -

25. All s orbitals are spherically
symmetrical. That is, an electron that
occupies an s orbital can be found with
the same probability at any orientation
from the nucleus.
2 S
When an electron is described by the wavefunction corresponding to a
particular orbital, the electron is said to occupy that orbital.
When an electron is described by the wavefunction corresponding to a
particular orbital, the electron is said to occupy that orbital.
All other orbitals have zero amplitude at the nucleus, and an electron that
occupies one of them has zero probability of being found there.
It is largely responsible, for instance, for the structure of the periodic table
and hence for the pattern of the compounds that the elements can form and
for the properties of the substances that make up the tangible world.

27. All p orbitals have adumbbell shape.
The Second kind of label are subscripts which distinguish between
orbitals which are basically the same shape but differ in their
orientation in space. In the case of p orbitals there are
always three orientations possible.
A p orbital which extends along the x axis is labeled a px orbital
and A p orbital along the y axis is labeled pyand one along
the z axis is a pz orbital.
When n equals 3, three orbital types occur.
so the 3s and 3p orbitals differ slightly in shape from the 2s and
2p orbitals.

28. 2Px and 2Py
2Pz

29. The d orbitals have more complex shapes than the p orbitals.
In the case of the dorbitals the subscripts are more difficult to
follow.
You can puzzle them out from the rotating images, the dot
density diagrams and the orbital surface diagrams if you like, but
analysis of these orbitals is usually considered beyond the scope
of general chemistry.
The same pattern extends to n = 4 where four orbital types,
namely, 4s, 4p, 4dand 4f, are found.
While none of these orbitals will be shown, the patterns seen in
moving from 1s to 2s or from 2p to 3p continue with the s, p,
and d orbitals

31. D ORBITALS

32. THANK YOU