Which of the following statements are correct? A. The process of the addition an electron to a neutral gaseous atom is always exothermic B. The process of removing an electron from an isolated gaseous atom is always endothermic C. The $1^{\text {st }}$ ionization energy of the boron is less than that of the beryllium D. The electronegativity of C is 2.5 in $\mathrm{CH}_{4}$ and $\mathrm{CCl}_{4}$ E. Li is the most electropositive among elements of group I Choose the correct answer from the options gives below

JEE Main · 2025 · 03 Apr 2025 · Shift 1 · Classification of Elements and Periodicity

Which of the following statements are correct?
A. The process of the addition an electron to a neutral gaseous atom is always exothermic
B. The process of removing an electron from an isolated gaseous atom is always endothermic
C. The

1^{st}

ionization energy of the boron is less than that of the beryllium
D. The electronegativity of C is 2.5 in

CH_{4}

and

CCl_{4}

E. Li is the most electropositive among elements of group I

Choose the correct answer from the options gives below

(A)B and C only✓ Correct
(B)A, C and D only
(C)B and D only
(D)B, C and E only

Answer: (A)

Solution

Adding an electron to a neutral gaseous atom is not always exothermic; for a stable closed shell it can be endothermic, so A is wrong. Removing an electron always requires energy, so B is correct. Beryllium's filled

2 s^{2}

shell makes its first ionisation energy greater than that of boron, whose outer

2 p^{1}

electron is removed more easily, so C is correct. Carbon's electronegativity is not fixed at

2.5

in both

CH_{4}

and

CCl_{4}

since it depends on the atoms bonded to it, so D is wrong, and caesium, not lithium, is the most electropositive group 1 element, so E is wrong. The correct statements are B and C.

JEE Main · 2025 · 03 Apr 2025 · Shift 1 · Single correct option

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JEE Main · 2025 · 03 Apr 2025 · Shift 1 · Classification of Elements and Periodicity

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