Question

How to find valency of elements above 20​

Answer 1

Answer:

divide them in different shells 2,8,8..... in this order

The number which is left in the last shell is its valency

Answer 2

kk
$= = = { {.3x = 33? \times \frac{?}{?} \times \frac{?}{?} }^{?} }^{?}$