Question

The general electronic configuration of representative elements is (a) \(\mathrm{ns}^{1-2} \mathrm{np}^{1-6}\) (b) \(\mathrm{ns}^{1-2} \mathrm{np}^{1-5}\) (c) \(\mathrm{ns}^{1-2}(\mathrm{n}-1) \mathrm{p}^{1-5}\) (d) \(\mathrm{ns}^{1-2}(\mathrm{n}-1) \mathrm{p}^{1-6}\)

Short answer

Answer: The correct general electronic configuration for representative elements is: - \(\mathrm{ns}^{1-2}\) for alkali metals (Group 1) and alkaline earth metals (Group 2). - \(\mathrm{ns}^{1-2} \mathrm{np}^{1-6}\) for p-block elements (Groups 13-18).

Step-by-step solution

Option (a) \(\mathrm{ns}^{1-2} \mathrm{np}^{1-6}\)

This option represents an element with 1 or 2 electrons in the s-subshell and 1 to 6 electrons in the p-subshell. It covers all p-block elements but fails to cover all alkali metals and alkaline earth metals, as the s-subshell needs to be completely filled in those cases. Hence, this option is not the correct general electronic configuration for representative elements.

Option (b) \(\mathrm{ns}^{1-2} \mathrm{np}^{1-5}\)

This option represents an element with 1 or 2 electrons in the s-subshell and 1 to 5 electrons in the p-subshell. It covers all alkali metals and alkaline earth metals, as well as the first five groups of p-block elements (Groups 13-17). However, it does not cover the last group of representative elements (Group 18) where the p-subshell is completely filled with 6 electrons. Hence, this option is not the correct general electronic configuration for representative elements either.

Option (c) \(\mathrm{ns}^{1-2}(\mathrm{n}-1) \mathrm{p}^{1-5}\)

This option incorrectly introduces a term \((\mathrm{n}-1)\) that is multiplied by the p-subshell configuration. This would not be the correct general expression for the electronic configuration of representative elements. Therefore, this option is incorrect.

Option (d) \(\mathrm{ns}^{1-2}(\mathrm{n}-1) \mathrm{p}^{1-6}\)

Similar to option (c), this option also incorrectly introduces a term \((\mathrm{n}-1)\) that is multiplied by the p-subshell configuration. This would not be the correct general expression for the electronic configuration of representative elements. Hence, this option is incorrect too. By eliminating the other options, the correct electronic configuration of representative elements would be a combination of original options (a) and (b), which is:

Correct electronic configuration

\(\mathrm{ns}^{1-2}\) for alkali metals (Group 1) and alkaline earth metals (Group 2).

and

\(\mathrm{ns}^{1-2} \mathrm{np}^{1-6}\) for p-block elements (Groups 13-18).

Key concepts

Representative Elements

Representative elements are key players in the periodic table. They are located in the first two groups and the last six groups on the periodic table. These include both the s-block and p-block elements.

Characteristics of representative elements include:

• They have a wide range of properties, from metals to nonmetals.
• Their outermost shells are not fully filled with electrons.
• They follow predictable trends in the periodic table.

Representative elements exhibit various oxidation states, and their properties are often a crucial part of chemical reactions and compounds.

s-subshell

The s-subshell is the simplest type of atomic orbital. It can hold a maximum of 2 electrons.

Key points about the s-subshell include:

• The first subshell filled in any given electron shell of an atom.
• Contributes to the shape and energy levels of atoms.
• Denoted by the symbol \(ns\) where \(n\) is the principal quantum number.

Understanding the s-subshell is vital for determining the electronic configuration of elements, especially for alkali and alkaline earth metals.

p-block

The p-block is part of the periodic table that includes groups 13-18. These elements are diverse and play important roles in chemical interactions.

Features of p-block elements include:

• Contain up to 6 electrons in their p-subshell.
• Include a blend of metals, metalloids, and nonmetals.
• Exhibit a wide variety of chemical behaviors.

These elements are crucial in industries and biological systems, contributing to the formation of many compounds.

Alkali Metals

Alkali metals belong to Group 1 of the periodic table. They have a single electron in their outermost s-subshell, leading to unique properties.

Characteristics of alkali metals:

• Highly reactive, especially with water.
• Soft and can be cut with a knife.
• Form strong ionic compounds.

Due to their reactivity, they are seldom found in nature in their pure form, always bonded with other elements.

Alkaline Earth Metals

Alkaline earth metals, located in Group 2, contain two electrons in the s-subshell. This influences their reactivity and overall properties.

Key points about alkaline earth metals include:

• Less reactive than alkali metals but still react with water.
• Form bonds predominantly in ionic compounds.
• Have higher melting points compared to alkali metals.

Alkaline earth metals are essential in various industries, including construction and medicine, due to their stability and suitable reactivity.