Question

Write the number of protons, electrons, and neutrons present in ${}_{17}{}^{35}\mathrm{Cl}$ element. Give the electronic configuration and draw the atomic diagram.

Answer 1

Atom is represented with its symbol having an atomic number in subscript and mass number in superscript. Symbolic representation is mentioned below :

For given element ${}_{17}{}^{35}\mathrm{Cl}$ :

Part-1 Find number of protons, electrons and neutrons:

The atomic number $\left(\mathrm{Z}\right)$ of an element is equal to the total number of protons present in the nucleus of the atom.

Atomic number = Number of protons = Number of electrons (for electrically neutral atom)

The atomic number of chlorine is $17$, so it has $17$ protons and hence number of electrons are also $17$.

The mass number of elements is equal to the sum of the total number of protons and neutrons present in the nucleus of the atom.

Mass number = Number of protons + Number of neutrons

Also, Number of neutrons = Mass number - Number of protons

The number of neutrons in chlorine$=$$35-17=18$.

Therefore, chlorine have $17$protons, $17$electrons and $18$ neutrons.

Part-2 Electronic configuration

Electronic configuration describes the distribution of electrons in different shells like $\mathrm{K},\mathrm{L},\mathrm{M},\mathrm{N}....$with principal quantum number $\left(\mathrm{n}\right)$ value $1,2,3,4...$respectively. According to formula $2{\mathrm{n}}^2$, maximum $2$ electrons can be filled in $\mathrm{K}$shell, $8$ in $\mathrm{L}$ and so on according to the formula. Therefore, an electronic configuration is $2,8$,$7$.

Shell	$\mathrm{K}$	$\mathrm{L}$	$\mathrm{M}$
Number of electrons filled	$2$	$8$	$7$

Part-3 Atomic Diagram: