Class 11th

Assertion (A) : Electron gain enthalpy becomes less negative as we go down a group.

Reason (R) : Size of the atom increases on going down the group and the added electron would be farther from the nucleus.

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

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

(iii) Assertion and reason both are wrong statements.

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

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

An element belongs to 3rd period and group-13 of the periodic table. Which of the following properties will be shown by the element?

(i) Good conductor of electricity

(ii) Liquid, metallic

(iii) Solid, metallic

(iv) Solid, non metallic

Ionic radii vary in

(i) Inverse proportion to the effective nuclear charge.

(ii) Inverse proportion to the square of effective nuclear charge.

(iii) Direct proportion to the screening effect

(iv) Direct proportion to the square of screening effect.

Which of the following have no unit?

(i) Electronegativity

(ii) Electron gain enthalpy

(iii) Ionisation enthalpy

(iv) Metallic character

In which of the following options order of arrangement does not agree with the variation of property indicated against it?

(i) Al³⁺ < Mg²⁺ < Na⁺ < F^– (increasing ionic size)

(ii) B < C < N < O (increasing first ionisation enthalpy)

(iii) I < Br < Cl < F (increasing electron gain enthalpy)

(iv) Li < Na < K < Rb (increasing metallic radius)

Which of the following sets contain only isoelectronic ions?

(i) Zn²⁺, Ca²⁺, Ga³⁺, Al³⁺

(ii) K⁺ , Ca²⁺, Sc³⁺, Cl ^–

(iii) P^3–, S^2–, Cl^– , K⁺

(iv) Ti ⁴⁺, Ar, Cr³⁺, V⁵⁺

Which of the following statements are correct? 

(i) Helium has the highest first ionisation enthalpy in the periodic table.

(ii) Chlorine has less negative electron gain enthalpy than fluorine.

(iii) Mercury and bromine are liquids at room temperature.

(iv) In any period, atomic radius of alkali metal is the highest.

Which of the following elements will gain one electron more readily in comparison to other elements of their group?

(i) S (g)

(ii) Na (g)

(iii) O (g)

(iv) Cl (g)