(i) What is stationary energy level of an electron?
(ii) State one difference between Rutherford and Bohr's model of atomic structure.
(iii) Write the electronic configurations of `Co^(2+) and As^(3+)` ions. (Atomic number of Co is 27 and As is 33).

Explanation

(i) According to Bohr's theory, the energy level in which no energy is emitted by an electron is known as the stationary energy level of that electron.
(ii) N/A
(iii) `""_(27)Co^(2+): 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(7)`
`""_(33)As^(3+): 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10)4s^(2)`