Explanation:
1-2 groups : alkali and alkaline earth metal group
It consist of metals (typical metals ).
3 to 12 : transition metals
13-17 : non metals
18group - Inert gases .
In 1st group the elements are :
Hydrogen (H)
Lithium (Li)
Sodium(Na)
Potassium (K)
Rubidium(Rb)
Cesium (Cs)
Francium (Fr)
There valence electron is one and valency shown by them is also +1.
Therefore , the charge on each is +1 .