Period

Period
o It is a horizontal row-row on periodic table.
o Modern SPU consists of period 7. Each period the number of states / atom skin many elements that occupy the period-period.
So:

Period number = Number of Skin Atom


o The number of elements in each period:




Period


Total Element


Atom ( Z )

1


2


1 – 2

2


8


3 – 10

3


8


11 – 18

4


18


19 – 36

5


18


37 – 54

6


32


55 – 86

7


32


87 – 118
Note:
a) Period 1, 2 and 3 called for a short period of relatively few elements
b) Period 4 and so-called long period
c) The period of 7 is called the period not yet complete because it has not come to class VIII A.
d) For a number of elements based on a number atomnya, you only need to know the atomic number elements that start each period

o elements that have 1 skin (skin K only) is located in the period 1 (line 1), the elements that have 2 skin (skin K and L) located in the period 2 .

Example :

9F = 2 , 7 period 2

12Mg = 2 , 8 , 2 period 3

31Ga = 2 , 8 , 18 , 3 period 4