please answer

Question

which has higher ionisation enthalpy and why

Be+ and Be

Answer 1

Hello Prakhar

 

Be⁺ has a greater ionization enthalpy than Be.  The removal of electrons from an atom requires energy.  In other words, this process is endothermic.

 

Since Be is in Group 2, it can lose 2 electrons.  The first ionization is:

 

Be + energy → Be⁺ + e^-

 

The second ionization is:

 

Be⁺ + energy → Be²⁺ + e^-

 

Be⁺ has 1 valence electron remaining in its outermost shell that feels a strong electrostatic interaction with the four protons in the nucleus (just think about positive-negative attraction).  To overcome this interaction, more energy is therefore needed to remove the 2nd electron from the valence shell to form Be²⁺.