Outermost electronic configurations of four elements A, B, C, D are given below :

(A) $$3 s^{2}$$

(B) $$3 s^{2} 3 p^{1}$$

(C) $$3 s^{2} 3 p^{3}$$

(D) $$3 s^{2} 3 p^{4}$$

The correct order of first ionization enthalpy for them is :

Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: Energy of $$2 \mathrm{s}$$ orbital of hydrogen atom is greater than that of $$2 \mathrm{s}$$ orbital of lithium.

Reason R: Energies of the orbitals in the same subshell decrease with increase in the atomic number.

In the light of the above statements, choose the correct answer from the options given below.

Which of the following sets of quantum numbers is not allowed?

The number of radial nodes and total number of nodes in 4p orbital respectively are :