Assertion (A): Boron has a smaller first ionization enthalpy than beryllium Reason (R): The penetration of a 2s electron to the nucleus is more than the 2p electron hence 2p electron is more shielded by the inner core of electrons than the 2s electrons.

Question

Assertion (A): Boron has a smaller first ionization enthalpy than beryllium Reason (R): The penetration of a 2s electron to the nucleus is more than the 2p electron hence 2p electron is more shielded by the inner core of electrons than the 2s electrons. (A) Assertion and reason both are correct statements but reason is not correct explanation for assertion (B) Assertion is correct statement but reason is wrong statement. (C) Assertion and reason both are correct statements and reason is correct explanation for assertion. (D) Assertion and reason both are wrong statements,

Tardigrade Admin · Accepted Answer

Assertion ( A ) Electronic configuration of boron (Z=5) is [ He ] 2 s2 2 p1 . So, in first ionisation (1 I E1. or .Δi H1) removal will take place from unpaired p1-electron. Whereas that of Be will be from paired 2 s2-electrons which requires more energy. Electronic configuration of Be(Z=4):[H e] 2 s2 So, the Assertion is a correct statement. Reason ( R ) s-orbital is being symmetrical in shape (spherical), it shields nuclear force (nuclear charge) strongly. So, 2 p1-electron of B is experiences lesser nuclear attractive force for ionisation. As a result, I E1 or Δi H1: B< Be So, the Reason is correct explanation for Assertion.

Q. Assertion (A): Boron has a smaller first ionization enthalpy than beryllium Reason (R): The penetration of a 2s electron to the nucleus is more than the 2p electron hence 2p electron is more shielded by the inner core of electrons than the 2s electrons.

Assertion and reason both are correct statements but reason is not correct explanation for assertion

Assertion is correct statement but reason is wrong statement.

Assertion and reason both are correct statements and reason is correct explanation for assertion.

Assertion and reason both are wrong statements,

Q. Assertion (A): Boron has a smaller first ionization enthalpy than beryllium
Reason (R): The penetration of a $2 s$ electron to the nucleus is more than the $2 p$ electron hence $2 p$ electron is more shielded by the inner core of electrons than the $2 s$ electrons.