MCQ practice · SSC Chemistry Board questions · Chapter 3: Structure of Matter
Which noble gas has 8 electrons in its N shell?
Think it through first, then pick an option.
- a Ne
- b Ar
- c Kr
- d Xe
Answer and explanation
Correct answer: c Kr
Kr (36) is 2, 8, 18, 8: exactly 8 in N.
Why the other options are wrong
- a Ne: Ne (10) is 2, 8: only two shells, no N.
- b Ar: Ar (18) is 2, 8, 8: three shells; the 8 are in M and N is empty.
- d Xe: Xe (54) is 2, 8, 18, 18, 8: the 8 sit in the fifth shell, O; N has 18.
More board questions on this topic
- How many valence electrons does element Y have?
- Look at these statements:
- How many subshells are there in the N shell of an atom?
- At most how many electrons can the 'K' level hold?
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