What do you mean by Electro negativity?

Explanation

Electro negativity is relative tendency of a bonded atom to attract the bond-electrons towards it. It just compares the tendency of various elements to attract the bond-electrons towards themselves.
(a) Electron negativity decreases in a group from top to bottom
(b) Electron negativity increases in a period from left to right
(c) Electro negativity is related to ionizatio energy. Electrons with low ionization energies have low electro negativity because their nuclei do nto exert a strong attractive force on electrons.
(d) Elements with high ionization energies have high electro negativity due to the strong pull exerted on electrons by the nucleus.