Question

In any group second period element exhibit anomalous properties. Correct statements about this is/are:

• A. All second-period elements exhibit a diagonal relationship.
• B. Generally, maximum covalency of the first member of each group cannot exceed four.
• C. Anomalous behavior is due to small size, large charge/radius ratio, and high electronegativity of the elements.
• D. The first member of the P-block element displays greater ability to form $\mathrm{p\pi }-\mathrm{d\pi }$ multiple bonds to itself and to the other second period elements, compared to subsequent members of the group

Answer 1

The correct option is C

Anomalous behavior is due to small size, large charge/radius ratio, and high electronegativity of the elements.

Explanation of correct option:-

Option (C):- Anomalous behavior is due to small size, large charge/radius ratio, and high electronegativity of the elements.

1. Anomalous properties of an element refer to the change or deviation of the properties of any element from its normal ones.
2. Atoms in the second period have a smaller size.
3. So, due to the small size of the atom, the charge is concentrated on a smaller nucleus with a high charge
4. So, second-period elements have a high charge to radius ratio.
5. These anomalous properties of the second-period element are because of the absence of d-orbital

Explanation of incorrect option:-

Option (A):- All second-period elements exhibit a diagonal relationship.

1. A diagonal relationship refers to the similarity in the properties of the definite pairs of the diagonally adjacent elements.
2. A diagonal relationship exists in the elements of the second and third period.
3. Elements till nitrogen ($\mathrm{N}$) in the second period show a diagonal relationship.

Option (B):- Generally, maximum covalency of the first member of each group cannot exceed four.

1. The Covalency of an element is determined by the number of electrons shared while the formation of the chemical compound.
2. The maximum covalency of the first elements of each group is 4 which is because of the small size of the elements, absence of d orbitals, and highly electronegative element.
3. But anomalous properties of the second-period elements are because of the small size, large charge/radius ratio, high electronegativity not only covalency,

Option (D):- The first member of the P-block element displays a greater ability to form $\mathrm{p\pi }-\mathrm{d\pi }$ multiple bonds to itself and the other second period elements, compared to subsequent members of the group

1. The first member of the P-block consists of elements like Boron $\left(\mathrm{B}\right)$, Carbon, Nitrogen $\left(\mathrm{N}\right)$, Oxygen $\left(\mathrm{O}\right)$, Fluorine$\left(\mathrm{F}\right)$, and Neon$\left(\mathrm{Ne}\right)$
2. These elements do not consist of d-orbitals.
3. Because of the absence of d-orbitals in its valence shell, the first member of the P-block element does not form $\mathrm{p\pi }-\mathrm{d\pi }$ bond.

Therefore, anomalous behavior is due to the small size, large charge/radius ratio, and high electronegativity of the elements.

Hence, option (C) is correct.