Answer : An atom is the smallest particle into which an element can be divided and still be the same substance.
Explanation :
Atom : It is the smallest unit of an element. Every atom is composed of a nucleus.
There are three sub-atomic particles present in every atom which are electrons, protons and neutrons.
The nucleus of an atom consist of protons and neutrons.
The electrons are revolve around the nucleus and are bound to the nucleus.
You would use a stopwatch. Hope this helps :D
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