In aluminium atom, the screening is due to

(A) 1s² only

(B) 1s², 2s² only,

(C) 1s² , 2s² , 2p⁶, 3s² only

(D) 1s² 2s² , 2p⁶ only

solution : screening effect : screening effect is observed in an atom having more electrons and particularly more electron shells.

as we know nucleus attract the electrons occupied in valence shell but there are repulsive forces acting between valance electrons and electrons present in the inner shells. due to this, force of attraction between Valence electrons and nucleus decreases. This effect is known as screening effect. it depends on number of electrons in the inner shells.

so the screening effect on Aluminium atom is due to electrons present in the inner shells.

i.e., 1s², 2s², 2p⁶ .

so the option (D) is correct choice.

Answer:

(D) 2s22p only is answer