Which subatomic particle identifies the atom

proton

Explanation:

The atoms is made from a nucleus and a electronic shell. The nucleus is composed from protons (positively charged) and neutrons (no charge). The electronic shell is defined by the presence of electrons (negativity charged).

Now a particular element is identified by the number of protons which have to be equal to the number of electrons in the electronic shell. A particular element may have the same number of protons but different number of neutrons, these are isotopes which have the same chemical properties.

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).