Ionisation enthalpy, electron gain enthalpy and electronegativity — NEET & JEE Questions

Question 1 · difficulty L1 · recall

Ionisation enthalpy is the energy required to

• A. remove an electron from an isolated gaseous atom
• B. add an electron to an atom
• C. break a covalent bond in any molecule
• D. remove a proton from a nucleus

Question 2 · difficulty L2 · understanding

Given below are two statements: Statement I: The correct order of electronegativity of fluorine, oxygen and nitrogen is $\mathrm{F}>\mathrm{O}>\mathrm{N}$. Statement II: The oxidation state of oxygen in $\mathrm{OF}_2$ is +2 and in $\mathrm{Na}_2 \mathrm{O}$ is -2 . In the light of the above statements, choose the correct answer from the options given below

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Question 3 · difficulty L2 · understanding

Elements X and Y belong to Group 15. The difference between the electronegativity values of ' X ' and phosphorus is higher than that of the difference between phosphorus and ' Y '. ' X ' & ' Y ' are respectively

• A. As & Bi
• B. Bi & N
• C. N & As
• D. $\mathrm{As}$ & $\mathrm{Sb}$

Question 4 · difficulty L2 · understanding

Electronic configuration of four elements A, B, C and D are given below : (A) $1 s^2 2 s^2 2 p^3$ (B) $1 s^2 2 s^2 2 p^4$ (C) $1 s^2 2 s^2 2 p^5$ (D) $1 s^2 2 s^2 2 p^2$ Which of the following is the correct order of increasing electronegativity (Pauling's scale)?

• A. $\mathrm{D}<\mathrm{A}<\mathrm{B}<\mathrm{C}$
• B. $\mathrm{A}<\mathrm{B}<\mathrm{C}<\mathrm{D}$
• C. $\mathrm{A}<\mathrm{C}<\mathrm{B}<\mathrm{D}$
• D. $\mathrm{A}<\mathrm{D}<\mathrm{B}<\mathrm{C}$

Question 5 · difficulty L2 · understanding

Which of the following electronegativity order is incorrect?

• A. $\mathrm{S}<\mathrm{Cl}<\mathrm{O}<\mathrm{F}$
• B. $\mathrm{Al}<\mathrm{Si}<\mathrm{C}<\mathrm{N}$
• C. $\mathrm{Al}<\mathrm{Mg}<\mathrm{B}<\mathrm{N}$
• D. $\mathrm{Mg}<\mathrm{Be}<\mathrm{B}<\mathrm{N}$

Question 6 · difficulty L2 · understanding

Given below are two statements : Statement I : The electronegativity of group 14 elements from $$\mathrm{Si}$$ to $$\mathrm{Pb}$$, gradually decreases. Statement II : Group 14 contains non-metallic, metallic, as well as metalloid elements. In the light of the above statements, choose the most appropriate from the options given below :

• A. Statement I is false but Statement II is true
• B. Both Statement I and Statement II are true
• C. Both Statement I and Statement II are false
• D. Statement I is true but Statement II is false

Question 7 · difficulty L2 · understanding

The correct order of electronegativity for given elements is:

• A. $$\mathrm{C}>\mathrm{P}>\mathrm{At}>\mathrm{Br}$$
• B. $$\mathrm{Br}>\mathrm{C}>\mathrm{At}>\mathrm{P}$$
• C. $$\mathrm{Br}>\mathrm{P}>\mathrm{At}>\mathrm{C}$$
• D. $$\mathrm{P}>\mathrm{Br}>\mathrm{C}>\mathrm{At}$$

Question 8 · difficulty L2 · understanding

Inert gases have positive electron gain enthalpy. Its correct order is :

• A. He < Ne < Kr < Xe
• B. He < Xe < Kr < Ne
• C. Xe < Kr < Ne < He
• D. He < Kr < Xe < Ne

Question 9 · difficulty L2 · understanding

The $1^{\text {st }}$ ionization enthalpy for Mg is $+737 \mathrm{~kJ} / \mathrm{mol}$. The most probable estimated value of the $2^{\text {nd }}$ ionization enthalpy of Mg is $\_\_\_\_$ .

• A. $-906 \mathrm{~kJ} / \mathrm{mol}$
• B. $-856 \mathrm{~kJ} / \mathrm{mol}$
• C. $+1450 \mathrm{~kJ} / \mathrm{mol}$
• D. $+590 \mathrm{~kJ} / \mathrm{mol}$

Question 10 · difficulty L2 · understanding

Given below are two statements : Statement (I) : The first ionisation enthalpy of the elements Na, Mg, Cl and Ar follows the order Na > Mg > Cl > Ar. Statement (II) : Among Ca, Al, Fe and B, the third ionisation enthalpy is very high for Ca. In the light of the above statements, choose the correct answer from the options given below :

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true