Electronic configuration; stability of half-filled and filled orbitals — NEET & JEE Questions

Question 1 · difficulty L1 · recall

The maximum number of electrons that can occupy one orbital is

• A. 2
• B. 1
• C. 4
• D. 6

Question 2 · difficulty L2 · understanding

The total number of isoelectronic species from the given set is ___________. $\mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{Al}, \mathrm{Mg}^{2+}, \mathrm{Na}^{+}, \mathrm{O}^{+}, \mathrm{Mg}, \mathrm{Al}^{3+}, \mathrm{F}$

Question 3 · difficulty L2 · understanding

The number of atomic orbitals from the following having 5 radial nodes is ___________. $$7 \mathrm{s}, 7 \mathrm{p}, 6 \mathrm{s}, 8 \mathrm{p}, 8 \mathrm{d}$$

Question 4 · difficulty L2 · understanding

Consider an imaginary ion $${ }_{22}^{48} \mathrm{X}^{3-}$$. The nucleus contains '$$a$$'% more neutrons than the number of electrons in the ion. The value of 'a' is _______________. [nearest integer]

Question 5 · difficulty L2 · understanding

$$\text { Match the LIST-I with LIST-II }$$ List-I Orbital List-II Radial nodes and nodal plane A. 2s I. 1 Radial node + two nodal planes B. 3s II. 1 Radial node + one nodal plane C. 3p III. 2 Radial nodes + No nodal plane D. 4d IV. 1 Radial node + No nodal plane Choose the correct answer from the options given below:

• A. A-IV, B-I, C-III, D-II
• B. A-IV, B-II, C-III, D-I
• C. A-III, B-I, C-IV, D-II
• D. A-IV, B-III, C-II, D-I

Question 6 · difficulty L2 · understanding

The number of radial node/s for $3 p$ orbital is :

• A. 3
• B. 2
• C. 1
• D. 4

Question 7 · difficulty L2 · understanding

Which one of the following sets of ions represents a collection of isoelectronic species? (Given : Atomic Number : $$\mathrm{F:9,Cl:17,Na=11,Mg=12,Al=13,K=19,Ca=20,Sc=21}$$)

• A. $$\mathrm{N}^{3-}, \mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{S}^{2-}$$
• B. $$\mathrm{Ba}^{2+}, \mathrm{Sr}^{2+}, \mathrm{K}^{+}, \mathrm{Ca}^{2+}$$
• C. $$\mathrm{Li}^{+}, \mathrm{Na}^{+}, \mathrm{Mg}^{2+}, \mathrm{Ca}^{2+}$$
• D. $$\mathrm{K}^{+}, \mathrm{Cl}^{-}, \mathrm{Ca}^{2+}, \mathrm{Sc}^{3+}$$

Question 8 · difficulty L2 · understanding

The number of s-electrons present in an ion with 55 protons in its unipositive state is

• A. 10
• B. 9
• C. 12
• D. 8

Question 9 · difficulty L2 · understanding

Outermost electronic configurations of four elements A, B, C, D are given below : (A) $$3 s^{2}$$ (B) $$3 s^{2} 3 p^{1}$$ (C) $$3 s^{2} 3 p^{3}$$ (D) $$3 s^{2} 3 p^{4}$$ The correct order of first ionization enthalpy for them is :

• A. (A) < (B) < (C) < (D)
• B. (B) < (A) < (D) < (C)
• C. (B) < (D) < (A) < (C)
• D. (B) < (A) < (C) < (D)

Question 10 · difficulty L2 · understanding

The number of radial and angular nodes in 4d orbital are, respectively

• A. 1 and 2
• B. 3 and 2
• C. 1 and 0
• D. 2 and 1