Question

Boron does not form B3+ ion why

Answer 1

As the Boron atom is small in size a large amount of energy is needed to remove 3 electrons from the boron atom. So Boron does not form B3+ ion.

The atomic number of Boron is 5. Its electronic configuration is 1s[2]2s[2]2p[1].

When one electron is removed from the p orbital a He-like fulfilled s orbital is left. This is highly stable. So the second ionization enthalpy is quite high.

Again when one electron is removed a half filled orbital is left. So the third ionization enthalpy is also quite high.

Since the total energy needed to make B3+ is the total of all the ionization enthalpies an enormous amount of energy is required to form it. 

Answer 2

As Boron atom is Small it can lose electrons easily …

when 3 electrons it loses ,

• it obtains Noble Gas Configuration