Question

How do you calculate the valance of the element from its electronic configuration? What is the valance of magnesium with atomic number 12 and sulphur with atomic number 16? How does the valance vary in going down in a group?​

Answer 1

In class 10th,

to calculate valency, we write first the ECG, then, we check electrons in the last shell.

If they are upto 4, the valency = no. of electron

If the electrons of last shell exceed 4, then, valency= 8-valance electrons

.I have told u the concept. Now solve the above two questions as an exercise

Answers are-:. Mg- +2

S-. -2

And, in a group, valency remains same bcoz outermost electron remain same.

If u r in 11 th class, then that's a shameful question. bcoz valency calculation must be at Ur tips then.