Question

Statement I: Lithium needs less energy to have an electron knocked off from its outermost orbit than does helium.

Statement II: Lithium has one electron in its outermost orbit which is loosely bound due to the repulsion of the inner orbit electrons.

• A. Statement I is true. Statement II is true. Statement II is the correct explanation of statement I.
• B. Statement I is true. Statement II is true. Statement II is not the correct explanation of statement I.
• C. Statement I is true. Statement II is false.
• D. Statement I is false. Statement II is false.

Answer 1

The correct option is A Statement I is true. Statement II is true. Statement II is the correct explanation of statement I.

The electronic configuration of Li is as follows -

K	L
2	1

The electron present in L shell experiences less attraction from the nucleus due to the increased distance of the shell. Also, it experiences repulsion from the electrons present in K shell. This further reduces the net effective nuclear force on it.

Hence, it is easier to knock off the outermost electron in lithium as compared to helium.