Of the following sets which one does NOT contain isoelectronic species?

• PO^-3₄,SO₄^-2, ClO₄^-

• CN^-, N₂, C₂^-2

• SO₃^-2, CO₃^-2,NO₃^-

• BO₃^-3,CO₃^-2,NO₃^-

Why two helium atoms do not combine to form He₂?

What are 'Lewis structures'?

Name the conditions for the formation of an ionic bond between two atoms.

What is crystal lattice?

What is electrovalency?

What bond is present in MgCl₂ molecules?

Two elements A and B have the electronic configuration as:
A = 1s²2s²2p⁶3s² and B = 1s²2s²2p⁵
Write the empirical formula of the substance containing A and B.

What type of bonding would you expect between:
(i) a metal and a non-metal
(ii) a non-metal and another non-metal?