Question

Calculate the no. Of electrons, protons and neutrons in atom of an element with atomic number 20 and mass number 40. Write the electronic configuration and draw the structure of atom.

Answer 1

Electrons 20
Protons 20
No of electrons=protons
Mass-no. Of protons=40-20=20
No of neutrons.

Answer 2

$electrons = protons = atomic \: no \\ 20electrons \: and \: 20protons \: \\ mass \: no \: - no \: of \: electrons = neutrons \: \\ thus \: 20neutrons$
Element with Atomic no 20 is Calcium