Answer:
The number of protons is equal to the mass number of the element. Since an element always has a different number of protons, the mass can indicate how many neutrons are in an isotope. Atoms of the same element can have a different number of neutrons. There are three naturally-occurring isotopes of carbon.
Explanation:
Answer:
There are 12 nanoseconds in 
.
Explanation:
We need to convert to nanoseconds.
We know that,
Now using unitary method to solve it such that,
So, there are 12 nanoseconds in .
Answer: obey the "law of conservation of mass".
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Metals :-
Group 1A - Alkali metals ( highly reactive metals)
Non-metals :-
Group 17 - Halogens ( highly reactive non-metals )
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