question_answer 51)

    Metallic radii of some transition elements are given below. Which of these elements will have highest density?

Element	Fe	Co	Ni	Cu
Metallic radii/pm	126	125	125	128

  (a) Fe             (b)Ni             (c) Co             (d) Cu

Answer:

                  (d) On moving left to right along period, metallic radius decreases while mass increases. Decrease in metallic radius coupled with increase in atomic mass results in increase in density of metal.                                                                            Hence, among the given four choices Cu belongs to right side of Periodic Table in       transition metal, and. it has highest density (89 g/cm3).