Question

An ion $M^{3+}$ contains 10 electrons and 14 neutrons Element M has valency equal to the valency of another element X which has five electrons less than Ar in its outermost shell Identify the elements M and X.

• A. Element M is Al and X is N
• B. Element M is N and X is Al
• C. Element M is Ne and X is B
• D. Both elements M and X are Al

Answer 1

The correct option is D Both elements M and X are Al

M(III)ion has 10 electrons and no of neutrons are also 10. It has atomic no.13 while element X has 5 electrons less than Ar i.e 18-5=13. So both of them are aluminium metal.