Q3 of 63 Page 92

Lithium atom has an atomic mass of 6u and three protons in its nucleus. How many neutrons does it have?

Atomic mass of Lithium (Li) = 6u

Number of protons in nucleus = 3


Number of neutrons = atomic mass – the protons


= 6 – 3 = 3


Lithium has 3 neutrons in the nucleus.


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