Question

In the long form of periodic table, the transition metals are placed in:
(A) s-block
(B) f-block
(C) d-block
(D) s and p block

Answer 1

Hint: Transition metals occupy the middle portions of the long periods of the periodic table of the elements between the groups present on the left-hand side and the one on right-hand side.

Complete step-by-step solution:
The elements in the periodic table are divided into four categories:
1. Main group elements
2. Transition metals
3. Lanthanides
4. Actinides
Transition metals are those metals that exhibit transitional behaviour between s and p block elements, having partially filled d or f subshell in any common oxidation state. These are the metallic elements that serve as a bridge between the two sides of the table.
The reason why they exist in d-block comes from the fact that their outer electronic configuration belongs to d-subshell. The valence electrons are partially or fully filled in the d-orbital of the penultimate energy level and in the outermost s orbital. The general electronic configuration for d block elements is –
\[(n - 1){d^{1 - 10}}n{s^{1 - 2}}\] where n = 4 to 7 in periods
These elements show metallic qualities, high electrical and thermal conductivity, and good tensile strength. Ionization energy of the d block elements s-block and smaller p-block elements. They are very hard and have high enthalpy of atomization. The elements can exhibit multiple oxidation states. They form coordination complexes with different ligands. Also, they have high melting and boiling points because of strong covalent bonding.

Hence, the correct option is (C).

Note: Not all elements of d block are considered as transitional elements. Elements like zinc, cadmium, and mercury of the column 12 have completely filled d orbital and have no vacant d orbital to exhibit transition element properties. Thus, all transitional elements are d block elements but vice versa is not true.