MCQ practice · SSC Chemistry Board questions · Chapter 3: Structure of Matter
How many electrons are in the last orbit of element M?
Think it through first, then pick an option.
- a 4
- b 5
- c 8
- d 15
Answer and explanation
Correct answer: b 5
Z = 15 (phosphorus): 2, 8, 5, so 5 in the last orbit.
Why the other options are wrong
- a 4: 4 is the last shell of silicon (14); Z = 15 means 2, 8, 5.
- c 8: 8 is the L shell's count; the last shell holds 5.
- d 15: 15 is the total number of electrons; the last shell has only 5.
Your account is open, so all 30,000+ MCQs from every chapter are yours. Start practising SSC Chemistry →
Want to keep going?
A free account carries you on to the next questions and opens 30,000+ MCQs from every chapter. Join before launch and Chirkut bundles are 60% off.
The ones you missed, worth one more look