Chemistry NCERT Exemplar Solutions Class 11th Chapter Three

This is a Assertion and Reason Type Questions as classified in NCERT Exemplar

Option (iii)

The Be has the electronic configuration of [He]2s² while B has the electronic configuration of [He]2s²2p¹ . As in Be the outermost orbital i.e. 2s is fully filled thus it provides extra stability to the Be compared to B. Apart from this 2s electron is more penetrated compared to the 2p electron for which 2p electron faces more shielding effect than that of 2s electron.

This is a Assertion and Reason Type Questions as classified in NCERT Exemplar

Option (ii)

The ionization energy depends upon two factors

(a) The effective nuclear charge.

(b)The e^- -e ^– repulsions.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Option (i)& (iii)

Aluminium is the element which is a metal and good conductor of electricity.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Option (i)& (iii)

Ionic radii decreases with the increase of the effective nuclear charge and increases with the increase of shielding effect or e^- - e ^- repulsion as it outweighs the effective nuclear charge effect.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Option (i)& (iv)

Both electronegativity and metallic character do not possess units as they both are qualitative properties not a quantitative property.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Option (ii)& (iii)

The ionization enthalpy of N is higher than that of F because it possess half filled orbital which provide it extra stability due to symmetry.

 As the atomic size of F is much smaller thus its electron gain enthalpy is lower than that of the Cl

This is a Multiple Choice Questions as classified in NCERT Exemplar

option (ii)& (iii)

Isoelectronic species/ions are those species that possess the same number of electrons.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Option (i), (iii)& (iv)

He with 1s² electronic configuration has the highest electron gain enthalpy in the periodic table. In any period the alkali metals have the lowest effective nuclear charge in that particular period for which its atomic radius is the highest in that period.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Option (i)& (iv)

Both S and Cl have the higher tendency to gain electrons in order to attain stable the nearest noble gas configuration i.e. of Argon.

This is a Multiple Choice Questions as classified in NCERT Exemplar

Option   (i)& (iv)

The s-block elements and p-block elements together are called representative elements.