Change set
Pick exam & year, then Go.
Question map
Not attempted
Correct
Incorrect
★
Bookmarked
Loading…
Q60
(CDS-I/2025)
Science & Technology › Basic Science (Physics, Chemistry, Biology) › Basic chemical principles
Answer Verified
Number of electrons present in the species H₂⁺, He, H₂ and O₂⁺ respectively are :
Result
Your answer:
—
·
Correct:
A
Explanation
The number of electrons in a chemical species is determined by the total number of electrons in its neutral constituent atoms, adjusted for any overall electrical charge. A positive charge indicates the loss of electrons.
- H₂⁺: A neutral H₂ molecule has 2 electrons (1 from each hydrogen atom). The +1 charge means 1 electron has been lost, resulting in 2 - 1 = 1 electron.
- He: Helium is a neutral atom with an atomic number of 2, so it contains 2 electrons.
- H₂: A neutral hydrogen molecule contains exactly 1 + 1 = 2 electrons.
- O₂⁺: A neutral O₂ molecule contains 16 electrons (8 from each oxygen atom). The +1 charge means 1 electron has been lost, resulting in 16 - 1 = 15 electrons.
Therefore, the sequence is 1, 2, 2, and 15.
How others answered
Each bar shows the % of students who chose that option.
Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
28%
got it right
✓ Thank you! We'll review this.
SIMILAR QUESTIONS
5 Cross-Linked PYQs
UPSC repeats concepts across years. Login to see how this question connects to 5 others.
Login with Google