An electron has a negative charge of one
An neutron has no charge (hence, neutral)
An proton has a positive charge of one
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To measure length scientists may use rulers, meter sticks, etc. and to measure mass they may use a balance.
Answer:
No. of atom =
no.of moles x avagardro's number xatomicity
= weight /molar mass x No x atomicity
=8.2/142 x6.02x10^23 x 4
=0.346 x 10^23(approximately)