Question

What is the magnitude of the charge, in coulombs, of a lithium nucleus containing three protons and four neutrons? (charge of a proton is 1.6 x 10-19 c)?

Answer 1

Answer: 4.8x10^-19 C

Answer 2

The neutrons are electrically neutral, so they have net charge of zero. Therefore we should count only the charge given by the protons.

The nucleus contains three protons; each proton has a charge of
`q=+1.6 \cdot 10^(-19) C`, therefore the net charge of the lithium nucleus will be

`Q=3 \cdot (+1.6 \cdot 10^(-19)C)=4.8 \cdot 10^(-19)C`