Question

Write the number of protons, neutrons and electron in each of the following isotopes2 1H , 18 8O , 19 9F , 40 20Ca

Answer 1

Answer:

• For $^2_1H$,

Number of protons = 1.

Number of neutrons = 2-1 = 1.

Number of electrons = 1.

• For $^{18}_8O$,

Number of protons = 8.

Number of neutrons = 16-8 = 8.

Number of electrons = 8.

• For $^{19}_9F$,

Number of protons = 9.

Number of neutrons = 19-9 = 10.

Number of electrons = 9.

• For $^{40}_{20}Ca$,

Number of protons = 20.

Number of neutrons = 40-20 = 20.

Number of electrons = 20.

Explanation:

Any element $X$ is represented as

$^{A}_{Z}X$

where,

$A$ = mass number of the element.

$Z$ = atomic number of the element.

The atomic number represent the total number of protons present in that element.

The mass number represents the sum of numbers of protons and neutrons in the element.

The number of electrons for a neutral atom is same as that of protons.

Therefore,

Number of protons = Z.

Number of electrons = Z.

The number of neutrons = number of (neutrons+protons) - number of protons = A-Z.