question_answer 65)

  Those elements impart colour to the flame on heating in it, the atoms of which require low energy for ionisation (i.e., absorb energy in the visible region of spectrum). The elements of which of the following groups will impart colour to the flame? (a) 2                                       (b) 13                                    (c) 1                                       (d) 17

Answer:

  (a, c) The elements of first and second groups, i.e., alkali and alkaline earth metals possess low ionisation energies and impart colour to the flame.