chemistry class 9 Salient features of long form periodic table

1. CHEMISTRY 9
SALIENT FEATURES OF LONG
FORM PERIODIC TABLE

2. PERIODIC TABLE
The periodic table is a tabular
arrangement of the chemical elements.
It is organized in order of increasing
atomic number.

3. SALIENT FEATURES:
1
The long form of modern periodic
table consists of seven rows called
periods

4. 2
First period consists of only two elements.
Second and third periods consist of 8
elements each. Fourth and fifth periods
consist of 18 elements each. Sixth period
has 32 elements while seventh period has
23 elements and is incomplete.

5. 3
Elements of a period show different
properties.

6. 4
There are 18 vertical columns in the
periodic table numbered 1 to 18 from
left to right, which are called groups.

7. 5
The elements of a group show similar
chemical properties.

8. 6
Elements are classified into four blocks
depending upon the type of the
subshell which gets the last electron.

9. BLOCKS

10. BLOCKS
On the basis of completion of a
particular subshell, elements with
similar subshell electronic configuration
are referred as a block of elements.

11. There are four blocks
•s-block
•p-block
•d-block
•f-block

13. s-block
s-block elements are the elements found
in Group 1 and Group 2 on the periodic
table. Valence electron of s-block
elements are found in ‘s’ subshell.

14. p-block
The p-block is the area of the periodic
table containing columns 3A to column
8A (columns 13-18), not including
helium. p-block elements, have valence
electrons in the p orbital.

15. d-block
d-block elements constitute the periods
4,5 and6 of the modern periodic table.
The valence electrons of
these elements fall under
the d orbital. d-block elements are also
referred to as transition elements or
transition metals.

16. f-block
The f block elements are the
lanthanides and actinides and are called
the inner transition elements. Their
valance electrons are found in f orbital