31.

Write the complete symbols for the nuclei having:
(i) atomic number 26 and mass number 55,
(ii) atomic number 4 and mass number 9

Find the number of electrons in K⁺ ion and Cl^- ion (Z for K = 19, CI = 17).

What is the number of electrons, protons, neutrons and nucleons in carbon-14?

Arrange the following type of radiations in increasing order of frequency:
(a) radiation from microwave oven
(b) amber light from traffic signal
(c) radiation from FM radio
(d) cosmic rays from outer space
(e) X-rays.

Give the expression for the angular momentum of a revolving electron in an atom.

The spectrum of He is expected to be similar to that of.....

Write the mathematical relation for determining the number of lines in the spectrum.

What is the maximum number of lines when an excited electron of a hydrogen atom in n = 5 drops from exicted state to the ground state?

Give Rydberg equation.