Question

Beryllium has higher ionization enthalpy than boron. This can be explained as :

• A. beryllium has higher size than boron hence its ionisation enthalpy is higher
• B. penetration of $2p-$electrons to the nucleus is more than the $2s-$electrons
• C. it is easier to remove an electron from $2p-$orbital as compared to $2s-$orbital due to more penetration of $s-$electrons
• D. ionisation energy increases in a period

Answer 1

Answer: (C)

it is easier to remove an electron from $2p-$orbital as compared to $2s-$orbital due to more penetration of $s-$electrons

Beryllium has higher ionization enthalpy than boron. This can be explained by the electronic configuration of the two:

$Be:1s^{2}2s^2$

$B:1s^{2}2s^{2}2p^1$

In $Be$, the completely filled $2s$ orbital has high penetration and provides extra stability whereas in $B$, the lower penetration of $2p$ makes it is easier to remove the electron and thus have lower ionization enthalpy.