You can get information about periods and groups of elements.. difference of groups and periods. About periodic table .. periodicity of properties .. properties that display periodicity ...than you will can info about shielding effect with electronic configuration of some elements ... and at the last you will get the information about atomic size or you can also say size of atom ... at the end each topic you will get short exercises with their answers which are so informative ..

1. FABRIKAM
PERIODS AND GROUPS OF
ELEMENTS
P r e s e n t i n g b y
S a m a n a Z e k r u l l a h

2. INTRO TO PERIODIC
TABLE:
• B y t h e e n d o f 1 8 t h c e n t u r y , 2 3
e l e m e n t s w e r e k n o w n , b y 1 8 7 0 —
6 5 , b y 1 9 2 5 — 8 8 , t o d a y t h e r e a r e
1 0 9 . T h e s e e l e m e n t s c o m b i n e t o
f o r m m i l l i o n s o f c o m p o u n d s . I t
i s v e r y d i f f i c u l t r a t h e r
i m p o s s i b l e t o r e m e m b e r
i n f o r m a t i o n c o n c e r n i n g
r e a c t i o n s , p r o p e r t i e s a n d a t o m i c
m a s s e s o f e l e m e n t s . S o w e
c l e a r l y n e e d s o m e w a y t o
o r g a n i z e o u t k n o w l e d g e a b o u t
t h e m .
• F o r u n d e r s t a n d i n g t h o s e , w e u s e
p e r i o d i c t a b l e .
• T h e p e r i o d i c t a b l e i s o n e o f t h e
m o s t i m p o r t a n t t o o l s i n
c h e m i s t r y . I t i s v e r y u s e f u l f o r
u n d e r s t a n d i n g a n d p r e d i c a t i n g
t h e p r o p e r t i e s o f e l e m e n t s .
2

3. FABRIKAM
WHAT IS
PERIOD AND
GROUP OF
ELEMENT…?
G r o u p s a n d P e r i o d s a r e t w o w a y s
o f c a t e g o r i z i n g E l e m e n t i n t h e
p e r i o d i c t a b l e .
o P e r i o d s a r e h o r i z o n t a l
r o w s ( a c r o s s ) t h e p e r i o d i c t a b l e .
o W h i l e G r o u p s a r e v e r t i c a l
c o l u m n s ( d o w n ) t h e p e r i o d i c
t a b l e .
3

4. FABRIKAM
POINT TO BE
NOTICED...
PERIODIC TABLE
 Atomic number
increases as you move
down a group(H-Li-
Na)or you move across
a period (H-He).

5. FABRIKAMFABRIKAM
MORE ABOUT PERIODS AND GROUPS OF
ELEMENT…
P e r i o d s i n P e r i o d i c
T a b l e
o The horizontal rows of the periodic table are called
Periods.
o There are varying number of element in periods.
o There are seven periods in the periodic table.
o First three periods are called short periods
o Remaining four periods are called long periods
o The properties of element gradually changes as you
move from left to right in a period.
G r o u p s i n P e r i o d i c
T a b l e
o The vertical columns of the periodic table are called
Groups or Family.
o There are varying number of elements in groups.
o There are 18 groups in the periodic table.
(METALS: IA__IIA)
(METOLIDES: IIIB__IVB__VB__VIB__VIIB__VIIIB__IB__IIB)
(NON-METALS: IIIA__IVA__VA__VIA__VIIA__VIIIA)
o The properties of elements get change as you go down in a
group.
5

6. FABRIKAM
ACTIVITY (II)
NUMBER OF ELEMENTS IN THE PERIODS OF THE
PEEIODIC TABLE
Periodic No. No. Of Elements
First …?
Second …?
Third ….?
Fourth …?
Fifth …?
Sixth …?
Seventh …?
6

7. FABRIKAM
ACTIVITY (II)
NUMBER OF ELEMENTS IN THE PERIODS OF THE
PEEIODIC TABLE
Periodic No. No. Of Elements
First 2
Second 8
Third 8
Fourth 18
Fifth 18
Sixth 18
Seventh 9
7

8. FABRIKAM
GROUP OR
FAMILY
o Some group of elements in the periodic table
have been given group names.
o For example metallic elements in Group 1A
are called alkali metals.
o Group IIA elements are called alkaline earth
metals.
o The Group VIIIA elements are called noble
gases because they do not readily undergo
chemical reactions.
8

9. FABRIKAM
ACTIVITY (II)
THE NAMES OF DIFFERENT FAMILIES IN THE PERIODIC
TABLE
GROUPS No. Of Elements
I (A) …?
II (A) …?
III (A) …?
IV (A) …?
V (A) …?
VI (A) …?
VII (A) …?
VIII (A) …?
9

10. FABRIKAM
ACTIVITY (II)
THE NAMES OF DIFFERENT FAMILIES IN THE PERIODIC
TABLE
GROUPS No. Of Elements
I (A) (The alkali metals) or (Lithium family)
II (A) (the alkaline earth metals) or (Beryllium family)
III (A) The Boron family
IV (A) The Carbon family
V (A) The Nitrogen family
VI (A) The Oxygen family
VII (A) The Halogen family
VIII (A) Inert or Noble gasses
10

11. FABRIKAM
PERIODICITY
O f P r o p e r t i e s

12. FABRIKAM
WHAT DOES
PERIODICITY OF
PROPERTIES
MEAN …?
o R e p e t i t i o n o f p r o p e r t i e s a f t e r a
c e r t a i n i n t e r v a l i s
c a l l e d p e r i o d i c i t y o f p r o p e r t i e s .
o I f e l e m e n t s a r e a r r a n g e d i n
i n c r e a s i n g o r d e r o f t h e i r a t o m i c
n u m b e r i n t h e p e r i o d i c t a b l e ,
t h e n e l e m e n t s r e p e a t
t h e i r p r o p e r t i e s a f t e r a d e f i n i t e
i n t e r v a l . 12

13. FABRIKAMFABRIKAM
PROPERTIES
THAT DISPLAY
PERIODICITY
…
o Ionization Energy
o Electronegativity
o Atomic Radius
o Electron Affinity

14. FABRIKAM
ACTIVITY (III)
LETS SEE HOW SMART ARE YOU…!??
QUESTIONS TO BE ANSWERED
o What does periodicity of properties mean..?
o Speak out few lines about periodic table..
o Name some elements according to their group..
o Name the properties that display periodicity..
o Define group and period of elements..
o In how many divisions is periodic table divided..?
14

15. FABRIKAM
ACTIVITY (III)
LETS CHECK THE ANSWERS…
ANSWERS OF THE QUESTIONS
o Repetition of properties after a certain interval is called periodicity of properties.
o The periodic table is one of the most important tools in chemistry. It is very useful for understanding and
predicating the properties of elements.
o Alkali metals – The metals of group 1: Li, Na, K, Rb, Cs, Fr.
o Ionization energy...Electronegativity…Atomic Radius…Electron affinity.
o Groups and periods are two ways of categorizing elements in the periodic table...
o 10 divisions.
15

16. FABRIKAM
SHIELDING
EFFECTA T T R A C T I O N B E T W E E N T H E N E U C L E U S
I N V A L A N C E S H E L L E L E C T R O N S

17. FABRIKAMFABRIKAM
WHAT IS
SHIELDING IN
CHEMISTRY…?
17
o Electrons in an atom can shield each
other from the pull of the nucleus.
o This effect, called as
the shielding effect, describes the
decrease in attraction between an
electron and the nucleus in any atom
with more than one electron shell.
o The more shielding that occurs, the
further the valence shell can spread
out.

18. FABRIKAMFABRIKAM
LEARNING
MORE ABOUT
SHIELDING
EFFECT…
o As you move from top to bottom in group,
the number of electronic shells increase.
So the number of electrons in the inner shell
also increase.
As a result shielding effect increases.
o As you move from left to right in a period,
the number of electrons in the inner shells
remains constant.
Therefore, shielding effect remains constant.
18

19. FABRIKAMFABRIKAM
ELECTR
ONIC
STRUCT
URE OF
MAGNES
IUM
19

20. FABRIKAMFABRIKAM
ELECTR
ONIC
STRUCTU
RE OF
BERYLLI
UM
20

21. FABRIKAMFABRIKAM
ELECTR
ONIC
STRUCT
URE OF
LITHIU
M
21

22. FABRIKAM
ACTIVITY (IV)
MOVING FOR MORE QUESTIONS…
QUESTIONS TO BE ANSWERED
o Which atom has more shells, Be or Mg…?
o Which atom has greater shielding effect, Be or Mg…?
o Which atom has greater number of shells, Li or Be…?
o Which atom has greater number of electrons between nucleus and valence shell, Li or Be..?
o Choose the elements whose atoms you expect to have greater shielding effect
I. Be or Mg
II. C or Si
22

23. FABRIKAM
ACTIVITY (IV)
LETS SEE HOW SMART ARE YOU…!??
ANSWERS OF THE QUESTIONS ABOVE
o Magnesium ( Mg ) has more shells.
o Mg has greater shielding effect as compare to Be.
o Li and Be atoms both have the same number of shells.
o Li and Be have same number of electrons between their nucleus and valance electron.
o Be or Mg
Mg atoms will have greater shielding effect.
o C or Si
Si atoms will have greater shielding effect.
23

24. FABRIKAM
ATOMIC SIZE
S I Z E O F A T O M S

25. FABRIKAM
SIZE OF ATOM
o A t o m i c s i z e i s t h e
d i s t a n c e b e t w e e n t h e
c e n t e r o f t h e n u c l e u s o f
a n a t o m a n d i t s o u t e r m o s t
s h e l l .
A T O M I C R A D I U S
o I n b a s i c c h e m i s t r y ,
t h e a t o m i c r a d i u s i s
d e f i n e d a s t h e s h o r t e s t
d i s t a n c e b e t w e e n
t h e a t o m ' s n u c l e i a n d t h e
o u t e r m o s t s h e l l o f
t h e a t o m . 25

26. FABRIKAM
ABOUT ATOMIC
RADIUS
o The atomic radius decreases in any given period as you
move across the period.
Example:
In going from lithium to beryllium, atomic size
decreases.
o The atomic radius increases in any given main group as
you move down the group of elements.
Example:
In going from Li to Na, atomic radius increases.

27. FABRIKAM
ACTIVITY (V)
COMPREHENSION
QUESTIONS
o Define atomic size in simple words…
o What happens to the atomic radius as you move across the period…?
o What happens to the atomic radius as you move down the group…?
o Choose the element whose atom you expect to have larger radius in each of the following
pairs:
I. Mg / Al
II. C / Si
27

28. FABRIKAM
ACTIVITY (V)
ANSWERS
ANSWERS OF THE QUESTIONS ABOVE
o The size of an atom is the average distance between the nucleus of an atom and the outer
electronic shell.
o As you move across the period, the atomic radius decreases.
o As you move down the group, the atomic radius increases.
I. Mg / Al
The larger atomic radius from this both is Magnesium (Mg)
II. C / Si
The larger atomic radius from this both is Silicon (Si)
28

29. FABRIKAM
HERE COMES THE END OF MY WORK
P r e s e n t e d b y :
S A M A N A Z E K R U L L A H