Question

How many protons, neutrons, electrons are in an ion of sulphur ( $S^{-2}$ )?

Answer 1

Hint: To know about the number of protons, neutrons and electrons present in an atom or molecule or ion we should know the atomic number of the element present in the molecule or ion. We should know the charge present in the given ion too.

Complete answer:
- In the question it is given that to find the number of protons, neutrons, electrons present in an ion of sulphur ( $S^{-2}$ ).
- We know the atomic number of sulphur is 16.
- Means Sulphur has 16 protons in its nucleus.
- The number of neutrons present in sulphur nucleus is 16.
- Coming to the number of electrons, the number of electrons present in a sulphur atom is 16 but we have to find the number of electrons in $S^{-2}$ .
- In $S^{-2}$ molecule the sulphur atom accepts two electrons, the number of electrons which are present in $S^{-2}$ is 18.
- Therefore the number of protons, neutrons, electrons present in an ion of sulphur ( $S^{-2}$ ) are 16 protons, 18 electrons and 16 neutrons.

Note:
If we know the atomic number of an element then only we can find the number of protons, neutrons and electrons present in it. The number of electrons in an element is equal to the atomic number of the respective element. $S^{-2}$ is called sulphide (-2) anion means the charge on the sulphur is ‘-2’ nothing but the sulphur atom accepts two electrons from the other atoms.