JEE Main 2023 (Online) 6th April Morning Shift | Periodic Table & Periodicity Question 79 | Chemistry

Which of the following elements have half-filled f-orbitals in their ground state?

(Given : atomic number $\mathrm{Sm}=62 ; \mathrm{Eu}=63 ; \mathrm{Tb}=65 ; \mathrm{Gd}=64, \mathrm{Pm}=61$ )

A. $\mathrm{Sm}$

B. Eu

C. $\mathrm{Tb}$

D. Gd

E. $\mathrm{Pm}$

Choose the correct answer from the options given below :

B and D only

A and $B$ only

$C$ and $\mathrm{D}$ only

A and E only

JEE Main 2023 (Online) 31st January Evening Shift

MCQ (Single Correct Answer)

-1

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R)

Assertion (A): The first ionization enthalpy of $3 \mathrm{~d}$ series elements is more than that of group 2 metals

Reason (R): In 3d series of elements successive filling of d-orbitals takes place.

In the light of the above statements, choose the correct answer from the options given below :

Both (A) and (R) are true and (R) is the correct explanation of (A)

(A) is true but (R) is false

Both (A) and (R) are true but $(\mathbf{R})$ is not the correct explanation of (A)

(A) is false but (R) is true

JEE Main 2023 (Online) 31st January Morning Shift

MCQ (Single Correct Answer)

-1

The correct increasing order of the ionic radii is

$$\mathrm{Cl^- < Ca^{2+} < K^+ < S^{2-}}$$

$$\mathrm{K^+ < S^{2-} < Ca^{2+} < Cl^-}$$

$$\mathrm{Ca^{2+} < K^+ < Cl^- < S^{2-}}$$

$$\mathrm{S^{2-} < Cl^- < Ca^{2+} < K^+}$$