NEET Practice Questions (MCQs) with Answers & Solutions

The general electron configuration of transition elements is \( (n – 1)d^{1-10} ns^{1-2} \\). This configuration indicates that the d-orbital can have 1 to 10 electrons and the s-orbital can have 1 to 2 electrons.

The correct electron configuration of Chromium (Cr) is $ [Ar] 3d^5 4s^1 $. This is because Chromium has an exceptional electronic configuration to achieve a more stable half-filled d-subshell. Normally, we would expect $ [Ar] 3d^4 4s^2 $, but one electron from the 4s orbital is promoted to the 3d orbital to give it a half-filled d-shell, which is particularly stable.

The correct electron configuration of Copper (Cu) is $ [Ar] 3d^{10} 4s^1 $. Copper also has an exceptional electron configuration where one electron from the 4s orbital is promoted to the 3d orbital to achieve a fully filled d-subshell, which is more stable. Normally, it would be $ [Ar] 3d^9 4s^2 $, but the fully filled d-orbital provides extra stability.

Cadmium (Cd) is not considered a transition element. Transition elements are defined as elements whose atoms have an incomplete d-subshell or which can give rise to cations with an incomplete d-subshell. Cadmium has a completely filled d^10 configuration in its ground state, both in its elemental form and in its common oxidation state (+2).

E°red of Ag is very high

Not all transition elements dissolve in acid. For example, some transition metals like gold (Au) and platinum (Pt) are resistant to dissolution in common acids. Transition elements are defined by their high melting points, paramagnetic properties, and various oxidation states.