Question

An element has two electron in its N shell .
1) what is it atomic number ?
2) state the position in periodic table ?
3) is it a metal or non metal ?
4) state the name assigned to this group ?

Answer 1

In an atom, electrons are filled in the shells in the increasing order of energy of K, L, M, N.....

In the K shell maximum number of electrons $=2$

In the L shell maximum number of electrons $=8$

In the M shell maximum number of electrons $=18$

In the N shell maximum number of electrons $=2$

Hence, total number of electrons $=2+8+18+2=30$

(1) The atomic number of atoms = Total number of electrons $=30$

(2) The electronic configuration $=1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}$

The period of element = Number of shells $=4$

Since the last elections enter in d - subshell. So, it is d -block element.

The group number for given element $=12$

(3) Since d - block element can easily lose electrons to form cation due to the poor shielding effect of d - subshell. Hence, the given element is a metal.

(4) The name assigned to the group of this element is $IIB$.