TREND IN PERIODIC TABLE

by • 01/08/2013 • GeneralComments (0)326

TREND IN PERIODIC TABLE

In periodic table atomic radius increases in a group from top to bottom to increase in orbits and decrease in a period from left to right due to increase in molecular charge.

 

IONIC RADIUS

When any atom loses or gains electron it becomes ion, in such a case its radius is called Ionic radius.

Na ——-> Na+ + e- (cation)

Cl ——-> Cl- (Anion)

 

i. The radius of cation is lesser than neutral atom due to increase in the attractive force of proton on electrons,

ii. The radius of Anion is greater than neutral atom due to decrease of the iso-electronic ions, radius decrease with increase in nuclear charge.

Na+ > Mg+2 > Al+3

0.95°A> 0.65°A > 0.50°A

 

IONIZATION POTENTIAL

The minimum amount of heat energy required to remove an electron from outer most shell of any gaseous atom, ion or molecule is called ionization potential.

 

TREND IN PERIODIC TABLE

Since ionization potential depends upon distance of removed electron from, nucleus so in group from top to bottom it decrease due to increase in radius and in period from left to right it increase due to decrease in radius.

ELECTRO NEGATIVITY:

The force of attraction by which any atom attracts shared pair of electron of any other atom towards itself is called its electro negativity.

The value of electro negativity helps to determine the nature of bond between two atoms. Atoms having difference of electro negativity greater than 1.7 produce ionic bond while if the difference is less than 1.7, then the bond is covalent bond.

 

TREND IN PERIODIC TABLE

In periodic table from top to bottom in a group electronegativity decreases due to increase in atomic size while in period from left to right it increases due to decrease in atomic size.

 

ELECTRON AFFINITY:

The amount of energy gain or lose by any neutral gaseous to gain in electron and become ion (-ve) is called electron Affinity.

This process is normally exothermic in nature.

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