A neutral atom of an element has 2, 8, 8, 1 configurati... – Chemistry

Chemistryhard · Past Paper

A neutral atom of an element has 2, 8, 8, 1 configuration. How many neutrons are in its isotope with mass 40?

A19

B21

C20

D39

✓ Correct Answer: B — 21

Total electrons = 19 (Potassium). Neutrons = Mass (40) - Atomic Number (19) = 21.

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