How is the number of neutrons in the nucleus of an atom calculated?
a. add the number of electrons and protons together.
b. subtract the number of electrons from the number of protons.
c. subtract the number of protons from the mass number.
d. add the mass number to the number of electrons.

The correct answer is Option c.

Explanation:

Neutrons are the subatomic particle which is present in the nucleus of an atom.

Mass number is defined as the sum of number of protons and number of neutrons that are present in an atom.

Mass number = Number of neutrons + Number of protons

Number of neutrons = Mass number - Number of protons

From the above information, the correct answer is Option c.

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).

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a