Elements with valency 2 are:

1. Always metals
2. Always non-metals
3. Can be metals or non-metals
4. Metalloids (semi metals)

Nucleus of an atom is composed of :

1. Electrons and neutrons
2. Protons and neutrons
3. Protons, neutrons and electrons
4. Electrons and protons

The maximum number of electrons that M shell can occupy is:

1. 18
2. 8
3. 2
4. 10

Which orbit is nearest to the nucleus of an atom?

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