alleryCompact high-strength magnets often use which group of elements?
ANoble gases
BHalogen gases
CAlkali metals
DRare-earth metals
Answer & Solution
Correct answer: D. Rare-earth metals
1. Rare-earth elements have partly filled f electron shells.
2. Their electron spins can align, giving very strong fields.
3. Gases, halogens and alkali metals are not used this way.
_Source: Wikipedia, Magnet, Rare-earth magnets and rare-earth-free permanent magnets_
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