State the meaning of the term –

(a) atom

(b) molecule

(c) radical – with a suitable example.

In the Modern Periodic Table – atoms of all elements are arranged according to the their increasing order of – atomic numbers. An atom of nitrogen has seven protons and seven electrons. State what would be its atomic number.

State the main points of contradiction of Dalton’s atomic theory by the Modern Atomic Theory.

Atoms of the same element or different elements combine to form a molecule. Give two examples each of –

(a) atoms of the same element

(b) atoms of different elements combining to form a molecule.