Question

Which of the following transition metal ions has the lowest density?

• A. Copper
• B. Nickel
• C. Scandium
• D. Zinc

Answer 1

Answer: (C)

Scandium

Answer 2

(1) = 8.95 (2) = 8.91

(3) = 3.0 (4) = 7.14.

Across the period atomic volumes decreases upto copper due poor shielding of d-orbital electrons and addition of extra electrons in inner orbitals and then increases in zinc due to interelectronic repulsions in completely filled d- and s-orbitals. Consequently densities increase from Sc to Cu and then decreases in Zn.