Q45 of 59 Page 34

Match the electronic configuration with electron gain enthalpy.


EXPLANATION


Electron gain enthalpy of elements having fully filled orbitals will be extremely positive as they do not want to lose their stability. So in the first case it is +48kJmol-1. In the second case s orbital has just one electron so this element has more tendency to donate electron but as it can also gain one electron to complete its s orbital so it has a low negative electron gain enthalpy. In the third case just one electron is required to fill the p orbital. Hence it has a very high negative electron gain enthalpy. In the fourth case as 2 more electrons are required so it has a negative electron gain enthalpy but it is less negative than the third case.


More from this chapter

All 59 →
43

Match the correct atomic radius with the element.

 44

Match the correct ionisation enthalpies and electron gain enthalpies of the following elements.

 46

In the following questions a statement of Assertion (A) followed by a statement of reason

(R) is given. Choose the correct option out of the choices given below each question.


Assertion (A) : Generally, ionisation enthalpy increases from left to right in a period.


Reason (R) : When successive electrons are added to the orbitals in the same principal


quantum level, the shielding effect of inner core of electrons does not increase very much


to compensate for the increased attraction of the electron to the nucleus.


(i) Assertion is correct statement and reason is wrong statement.


(ii) Assertion and reason both are correct statements and reason is correct explanation of assertion.


(iii) Assertion and reason both are wrong statements.


(iv) Assertion is wrong statement and reason is correct statement.


 47

In the following questions a statement of Assertion (A) followed by a statement of reason

(R) is given. Choose the correct option out of the choices given below each question.


Assertion (A) : Boron has a smaller first ionisation 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.


(i) Assertion and reason both are correct statements but reason is not correct explanation


for assertion.


(ii) Assertion is correct statement but reason is wrong statement.


(iii) Assertion and reason both are correct statements and reason is correct explanation


for assertion.


(iv) Assertion and reason both are wrong statements.