Question

The following table shows the positions of four elements A, B, C and D in the periodic table.
Group →→ 1 2 3 to 12 13 14 15 16 17
Period ↓↓
2 A B
3 C D
Using the above table answer the following questions.

Which element will form only covalent compounds?
Which element is a metal with valency 2?
Out of C and D which one has bigger atomic radius and why?

Answer 1

Answer:

carbon

Helium

D it has more number of shells

Answer 2

(a)Which element will form only covalent compounds?

ans: 14th group.

(b)Which element is a metal with valency 2?

ans: 2nd group.

(c)Out of C and D which one has bigger atomic radius and why?

ans: the one with less atomic number and C ha bigger atomic radius than D because as we move from left to right atomic mass decreases in a period  due to  increase in nuclear charge which tends to pull the electrons closer the nucleus and reduces the size of the atom .