Which orbit is nearest to the nucleus of an atom?

1. K
2. L
3. M
4. N

Atoms combine to attain an electronic configuration similar to their nearest :

1. Metals
2. Noble gas
3. Non-metals
4. Semi metals

Name the following:

(a) The element which does not contain any neutron in 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.

Match the atomic numbers 4, 14, 8, 15 and 19 with each of the following :

(a) A solid non-metal of valency 3.

(b) A gas of valency 2.

(c) A metal of valency 1.

(d) A non-metal of valency 4.