Match the entries of column I with appropriate entries of column II and choose the correct option out of the four options given.
| Column I (Property) | Column II (Metal) |
| (i) Element with highest second ionisation enthalpy | (a) Cr |
| (ii) Element with highest third ionisation enthalpy | (b) Cu |
| (iii) M in M(CO)6 is | (c) Zn |
| (iv) Element with highest heat of atomisation | (d) Ni |
Answer & explanation
Correct answer: option 3
(i) Cu+: [Ar]3d10, which is very stable configuration. Hence, removal of 2nd electron requires very high energy.
(ii) Zn2+: [Ar]3d10 Hence, removal of 3rd electron requires very high energy.
(iii) Metal carbonyl with formula M(CO)6 is Cr(CO)6.
(iv) Ni has highest enthalpy of atomisation.