List of practice Questions

How much energy is required to ionise a H atom if the electron occupies n = 5 orbit? Compare your answer with the ionization enthalpy of H atom (energy required to remove the electron from n = 1 orbit).

The electron energy in hydrogen atom is given by \(E_n = \frac {(–2.18×10^{–18})}{n^2} \ J\). Calculate the energy required to remove an electron completely from the n = 2 orbit. What is the longest wavelength of light in cm that can be used to cause this transition?

The mass of an electron is 9.1 × 10^–31 kg. If its K.E. is 3.0 × 10^–25 J, calculate its wavelength.

How many electrons in an atom may have the following quantum numbers?

1. n = 4, m_s = – \(\frac 12\)
2. n = 3, l = 0

A certain particle carries 2.5 × 10^–16 C of static electric charge. Calculate the number of electrons present in it.