ICSE CHEMISTRY - Periodic table

ICSE CHEMISTRY - Periodic table

Periodic Table

Ø The arrangement of elements in Periodic table made easy to study their properties.

Ø The elements are arranged in the increasing order of their atomic numbers.

-          Atomic number is equal to the number of electrons in the orbits ( or energy shells) of an atom.

Ø Modern periodic law -“The physical and chemical properties of elements are the periodic functions of their atomic number”.

ü  Modern Periodic Table has 18 Groups (vertical columns) and 7 Periods (horizontal rows).

ü  The elements belonging to a particular group have same number of valence electrons.

ü  The period number indicates the number of shells in the atom of an element.

Modern Periodic table (Long form of Periodic table)

valency

1+

2+

3+

4

3-

2-

1-

0

No. of valence electrons

1

2

3

4

5

6

7

8

GROUP NUMBER

IA

IIA

IIIA

IVA

VA

VIA

VIIA

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

PERIOD 1 1 shell

H- 1

He-2

PERIOD 2 2 shells

Li 2,1

Be 2,2

B   2,3

C   2,4

N   2,5

O     2,6

F             2,7

Ne        2,8

PERIOD 3 3 shells

Na        2,8,1

Mg      2,8,2

Al       2,8,3

Si         2,8,4

P        2,8,5

S      2,8,6

Cl         2,8,7

Ar        2,8,8

PERIOD 4 4 shells

K       2,8,8,1

Ca    2,8,8,2

Br

Kr

PERIOD 5

Rb

Sr

I

Xe

PERIOD 6

Cs

Ba

At

Rn

PERIOD 7

Fr

Ra

ALKALI METALS

ALKALINE EARTH METALS

TRANSITION ELEMENTS (METALS)

HALOGENS

NOBLE GASES