alleryWhich series shows elements in order of decreasing atomic radius?
AAl > Na > Mg > Si
BSi > Al > Mg > Na
CMg > Al > Si > Na
DNa > Mg > Al > Si
Answer & Solution
Correct answer: D. Na > Mg > Al > Si
1. Na, Mg, Al and Si all belong to period 3 of the periodic table.
2. Atomic radius decreases across a period due to rising nuclear charge.
3. The leftmost element (Na) has the largest atomic radius.
4. Each subsequent element to its right is smaller in size.
5. So the decreasing order is Na, Mg, Al, Si.
6. The other options do not follow this monotonic trend.
_Source: Selina Concise Chemistry ICSE Class 10, Ch 1 'Periodic Table' (aplustopper.com extract)_
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