Question

Name the following :

(a) The element which does not contain any neutron m its nucleus.

(b) An element having valency 'zero'.

(c) Metal with valency 2.

(d) Two atoms having the same number of protons and electrons but different number of neutrons.

(e) The shell closest to the nucleus of an atom.

Answer 1

(a) Hydrogen
(b) Noble gases (18th Group elements). Example, Helium
(c) Alkali earth metals. Example, Magnesium
(d) Isotopes
(e) K shell (n=1, it means first orbit).