Question
Which of the following species are isoelectronic?
A. S$^{2-}$
B. C$^{4-}$
C. Mg$^{2+}$
D. O$^{-}$
E. Al$^{3+}$
Choose the correct answer from the options given below:
This question was previously asked in
CUET PG 2026 Agri-Business Management Question Paper (25-Mar-2026) (Shift 2)
The correct answer is
B, C, E only
Identifying Isoelectronic Species: MCQ Solution
Isoelectronic Species Definition
Isoelectronic species are atoms or ions that possess the same number of electrons. This means they have identical electronic configurations.
Electron Count Calculation for Each Species
The number of electrons in an ion is calculated by taking the atomic number (number of protons, which equals electrons in a neutral atom) and adjusting for the charge.
| Species | Atomic Number (Z) | Charge | Total Electrons |
|---|---|---|---|
| A. S$^{2-}$ | 16 | -2 | $16 + 2 = 18$ |
| B. C$^{4-}$ | 6 | -4 | $6 + 4 = 10$ |
| C. Mg$^{2+}$ | 12 | +2 | $12 - 2 = 10$ |
| D. O$^{-}$ | 8 | -1 | $8 + 1 = 9$ |
| E. Al$^{3+}$ | 13 | +3 | $13 - 3 = 10$ |
Determining Isoelectronic Sets
Based on the electron counts:
- S$^{2-}$ has 18 electrons.
- C$^{4-}$, Mg$^{2+}$, and Al$^{3+}$ each have 10 electrons.
- O$^{-}$ has 9 electrons.
Therefore, the species C$^{4-}$, Mg$^{2+}$, and Al$^{3+}$ (B, C, and E) are isoelectronic as they all contain 10 electrons.
Final Answer Selection
The correct option is the one listing species B, C, and E.
Was this answer helpful?
Similar Questions
- A solution containing 8.3 per dm$^3$ of Urea (molar mass = 60 g mol$^{-1}$) if found to be isotonic with 5% solution of non volatile organic solute A. The approximate molar mass of A is
- Choose the correct statement about para & ortho Hydrogen
A. Total spin of ortho hydrogen is zero.
B. Total spin of para hydrogen is zero.
C. The physical properties of two forms are different.
D. The chemical properties of two forms are different.
E. At higher temperature ortho is more stable.
Choose the correct answer from the options given below: - The root mean square velocity of a gas is given by
- Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Mass and volume are extensive properties.
Reason R: The ratio of mass to volume is also an extensive property.
In the light of the above statements, choose the most appropriate answer from the options given below - The parameters of Unit Cell in Hexagonal Crystal System is
- Cold light emission by glow worms is an example of
- In Cu atom $Z_{\text{eff}}$ value for 3d & 4s $e^-$ are respectively
- The molar conductance of NH$_4$Cl, NH$_4$NO$_3$ and AgNO$_3$ at infinite dilution are x, y & z Sm$^2$ mol$^{-1}$ respectively. The molar conductance of AgCl at infinite dilution is
- Which of the following has highest spin only magnetic moment.
- Match the LIST-I with LIST-II
LIST-I LIST-II A. Alkaline Earth metals I. s - block B. Transition Elements II. p - block C. Transuranic Elements III. d - block D. Metalloid IV. f - block
Choose the correct answer from the options given below:
Important Questions from Mixed Topic (CUET PG)
- Kalpsutra, the illustrated canonical text is from:-
- The Harappan city almost exclusively devoted to craft production was-:
- Mohandas Karamchand Gandhi launched quit India movement after the failure of:-
- The "Objectives Resolution" was introduced in constituent assembly by:-
- Who among the following was not a member of the constituent assembly:-
Need Expert Advice?
Upcoming Exams
GATE
February 06, 2027
Test Series
CUET
CUET PG Psychology (HUQP20) 2026 Mock Test Series
10 Tests
781 Attempts
3.7(15)
English
More Questions from CUET PG
