Question

An electron will be excited only when it absorbs                             [ Select ]                       ["the same", "more", "less"]         energy as the difference between orbital shells. This is because electron energy is                             [ Select ]                       ["quanitized", "quantified", "inefficient"]       .

Answer 1

Solution:

An electron will be excited only when it absorbs the same energy as the difference between orbital shells. This is because electron energy is quantized.

Explanation:

According to the Bohr's model,

For an atom with atomic number Z, energy of its orbital with princial quantum number 'n' is given by the formula:

The statement that electron energy is quantized means that the energy of electron at every orbital level is fixed i.e. the electrons have a particular value of energy for every principal quantum number 'n'.

For example,

For Hydrogen atom, Z = 1

and for different values of 'n', we have

E₁ = -13.6 eV

E₂ = -3.4 eV

E₃ = -1.51 eV

E₄ = -0.85 eV

......

.......

.......

E_n = (13.6)/n² eV

Since electrons have a fixed value of energy for every orbital, therefore it will only be excited if it absorbs energy equal to the difference in energy between orbital shells.

For example,

An electron of a hydrogen atom will only be excited from n = 1 to n = 2 level ,

if the energy absorbed by that electron atom will be equal to E₂ - E₁ = -3.4 eV - (-13.6 eV) = + 10.2 eV.