Representative elements are those which belong to

The correct option is s and p – Block.

To understand why representative elements belong to the s-block and p-block of the periodic table, let's break down the classification and эл��ктрон configurations of these elements:

1. Definition of Representative Elements:
Representative elements (also known as main-group elements) are those chemical elements in which the outermost s or p subshells are incomplete or newly filled. These groups represent the most common and abundant elements on Earth, showing clear periodic trends in their physical and chemical properties.

2. Group Distribution:
The representative elements include:
• s-Block Elements: These belong to Groups 1 (alkali metals, excluding hydrogen in some classifications) and 2 (alkaline earth metals). Their valence shell electron configuration is ${\mathrm{ns}}^{1–2}$.
• p-Block Elements: These belong to Groups 13 through 18 (boron family, carbon family, pnictogens, chalcogens, halogens, and noble gases). Their valence shell electron configuration is ${\mathrm{ns}}^2{\mathrm{np}}^{1–6}$ (with the exception of Helium, which has a ${\mathrm{1s}}^2$ configuration but behaves as a noble gas).

3. Contrast with other blocks:
• d-Block Elements: These are known as transition elements because they lie between the highly electropositive s-block and highly electronegative p-block elements, having partially filled d-orbitals.
• f-Block Elements: These are known as inner transition elements (lanthanides and actinides), where the f-orbitals are progressively filled.

Therefore, the elements belonging to the s and p – Block are collectively termed representative elements.