Question

First ionization enthalpy of boron (z=5) is slightly less than that of beryllium (z=4)

Answer 1

the reason is ....
Boron =1s2 2s2 2p1, and
Beryllium=1s2 2s2
Here in 2s2and 2p1, 2s2 is more closer to the necleus hence the ionization enthalpy is m
is maximum in this case so boron is slightly less than beryllium.... m

Answer 2

Answer: Beryllium has stable electronic configuration than boron.

Explanation:

Ionization enthalpy is defined as the energy required to remove an electron from its outermost shell

Beryllium is the 4th element of the periodic table and boron is the 5th element.

The valence electronic configuration of beryllium and boron is:

Beryllium (Z=4) : $2s^2$

Boron (Z=5) : $2s^22p^1$

It is known that the fully filled and half-filled orbitals are more stable than the partially filled electrons.

As, beryllium element has fully filled s-orbital and hence, will require more energy to remove an electron from its outermost orbital than boron element.

Hence, boron has less first ionization enthalpy than beryllium.