Question

The atomic of weight of an element is $23$ and its atomic number is $11.$ The number of protons, electrons and neutrons respectively present in the atom of the element are:
(A) $11,11,12$
(B) $12,12,11$
(C) $11,12,11$
(D)$12,11,12$

Answer 1

Hint:Electrons are the negatively charged particles of an atom. All of the electrons of an atom create a negative charge that balances the positive charge of the protons in the atomic nucleus. Protons are positively charged particles found within an atomic nucleus, a positive electric charge equal in magnitude to that of an electron. Neutrons are about the same mass as a proton but it is just without an electric charge which is present in all atomic nuclei except those of ordinary hydrogen.

Complete answer:
The atomic number of a chemical element is the number of protons found in the nucleus of every atom of that element. Its symbol is Z. Moreover, atomic numbers uniquely identify a chemical element. It is identical to the charge number of the nucleus.
So, here in this question the atomic number of the element is $11.$ Hence it contains $11$ protons and $11$ electrons since the element is neutral. Its mass number that is atomic weight is $23$ which is the total number of protons and neutrons together that is known as nucleus. Moreover, the mass number is different for each different isotope of a chemical element.
Therefore,
$\text{Mass Number} = Protons{\text{ }} + {\text{Neutrons}}$
If you want to calculate the no. of neutrons of an atom or element, you can simply subtract the number of protons or atomic number from the mass number. So, the number of neutrons of this element is $(23 - 11)$ that is $12$ neutrons.

Additional information:-
The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom that is (M) equal to the sum of the number of protons and neutrons in the nucleus. The no. of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).

Note:
The positive charge on a proton is equal in magnitude to the negative charge on an electron. So as a result, a neutral atom must have an equal number of protons and electrons. The number of protons in the nucleus of every atom of an element is always the same, but this is not the same with the number of neutrons. Atoms of the same element can have a different number of neutrons. Moreover, atoms want to have the same number of neutrons and protons but the number of neutrons can change.