Question

calculate the number electrons,protons and neutrons in an atom of an element with atomic number 20 and mass number 40. write the electronic configuration and draw the structure of the atom

Answer 1

Atomic number = 20
Mass number = 40

No. of protons = Atomic no. = 20
No. of neutrons = mass no.-Atomic no. = 40-20 = 20
No. of electrons = no. of protons = 20

Electronic configuration = 2,8,8,2

The structure of the atom, that is calcium is as ;

Answer 2

Given,

The atomic number of the element = 20

The mass number of the element = 40

To find,

We have to find the number of electrons, protons, and neutrons in an atom of an element with atomic number 20 and mass number 40 and the electronic configuration. We have to draw the structure of the atom also.

Solution,

It is given that atomic number = 20

We know that,

The atomic number of an element = number of electrons = number of protons.

Then, the number of electrons in an atom = 20

        the number of protons in an atom = 20

We know that,

  Mass number = number of protons/electrons + number of neutrons

                     40 =  20 + number of neutrons

               40-20 = number of neutrons

        Number of neutons = 20

Electronic configuration = 1s²2s²2p⁶3s²3p⁶4s².