The order of first ionisation energies of the elements Li, Be, B, Na is

Question

The order of first ionisation energies of the elements Li, Be, B, Na is (A) Li > Be > B > Na (B) Li < B < Be < C (C) Na > Li > B > Be (D) Be > Li > B > Na

Tardigrade Admin · Accepted Answer

As we go from left to right in a period, the ionization potential increases. Be and

B

are exceptions.
As Be has electronic configuration

1 s^{2} 2 s^{2}

and

B

has

1 s^{2} 2 s^{2} 2 p^{1}

, it's easy to remove electron from boron than beryllium.

Q. The order of first ionisation energies of the elements Li, Be, B, Na is

Li > Be > B > Na

Li < B < Be < C

Na > Li > B > Be

Be > Li > B > Na

As we go from left to right in a period, the ionization potential increases. Be and B are exceptions. As Be has electronic configuration 1s22s2 and B has 1s22s22p1, it's easy to remove electron from boron than beryllium.

As we go from left to right in a period, the ionization potential increases. Be and $B$ are exceptions.
As Be has electronic configuration $1 s^{2} 2 s^{2}$ and $B$ has $1 s^{2} 2 s^{2} 2 p^{1}$ , it's easy to remove electron from boron than beryllium.