Problem 101 - A Complete Resource Book in Chemistry for JEE Main

Question

Match the following: List I List II 1\. element with highest (i) \(\mathrm{I}_{2}\) electronegativity 2\. element with highest (ii) \(\mathrm{Br}_{2}\) electron affinity 3\. liquid non metal (iii) \(\mathrm{Cl}_{2}\) 4\. metallic solid (iv) \(\mathrm{F}_{2}\) The correct matching is: (1) (2) (3) (4) (a) (iii) (ii) (i) (iv) (b) (iv) (iii) (i) (ii) (c) (ii) (iii) (iv) (i) (d) (i) (ii) (iii) (iv)

Step-by-Step Solution

Answer

The correct matching is option (b).

Step 1: Understand the Match Options

There are pairs given in List I and List II. We need to match each item in List I with the correct item from List II based on characteristics such as highest electronegativity, highest electron affinity, liquid state, and metallic nature.

Step 2: Identify Element Characteristics (Step 1)

We know that Fluorine (F_{2}) has the highest electronegativity among the elements listed.

Step 3: Identify Element Characteristics (Step 2)

Chlorine (Cl_{2}) is known to have the highest electron affinity among the elements provided.

Step 4: Identify Element Characteristics (Step 3)

Bromine (Br_{2}) is the only liquid nonmetal at room temperature in the list.

Step 5: Identify Element Characteristics (Step 4)

Iodine (I_{2}) exists as a metallic solid in its elemental state.

Step 6: Match List I with List II

Using the identified characteristics, match as follows: 1. Element with highest electronegativity: F_{2} (iv) 2. Element with highest electron affinity: Cl_{2} (iii) 3. Liquid non-metal: Br_{2} (ii) 4. Metallic solid: I_{2} (i)

Step 7: Select the Correct Option

Match these with their corresponding positions: 1 - (iv) 2 - (iii) 3 - (ii) 4 - (i) This corresponds to option (b).

Key Concepts

Electronegativity

Electronegativity is a measure of how strongly an atom can attract or hold onto electrons in a chemical bond. Think of it like a tug-of-war, where the atom with higher electronegativity pulls the electrons closer to itself. This concept is central to understanding how atoms interact in molecules.
If an atom draws electrons closer, it gains a partial negative charge, while the other atom becomes partially positive. This helps explain why some molecules are polar, having a positive and negative side.

• Fluorine ( F_{2} ) has the highest electronegativity of all elements; hence, it tends to attract electrons strongly in a bond.
• The electronegativity scale was developed by Linus Pauling, and it typically ranges from about 0.7 for francium (lowest) to 3.98 for fluorine (highest).

Understanding electronegativity helps predict bond types. For example, with a substantial difference in electronegativity, atoms form ionic bonds.

Electron Affinity

The electron affinity of an element is the amount of energy released when an electron is added to a neutral atom. It's the opposite of ionization energy, which measures how much energy is needed to remove an electron.
An element with high electron affinity tends to gain electrons more readily. This trait is important in defining how reactive an element might be, especially with nonmetals.

• Chlorine ( Cl_{2} ) is known for having one of the highest electron affinities. It releases a significant amount of energy when it gains an electron, becoming more stable.
• Typically, nonmetals have higher electron affinities than metals since they tend to gain electrons to fill their outer electron shells.

Understanding electron affinity helps explain reactions and why certain elements readily form anions—ions with a negative charge.

Liquid Nonmetal

The term 'liquid nonmetal' refers to the physical state of certain elements at room temperature. Most nonmetals are gases or solids, but some can be found as liquids.
Bromine ( Br_{2} ) is unique among common nonmetals because it is a liquid at room temperature. This trait is rather unusual in comparison to other nonmetals which are typically found in gaseous or solid states at similar conditions.

• Bromine has a dark, reddish-brown color and a strong, unpleasant smell.
• It has applications in areas like flame retardants, and its liquid form is very reactive.

Understanding liquid nonmetals like bromine helps comprehend diversity in the states of matter that nonmetals can exhibit at standard conditions.

Metallic Solid

When we talk about a metallic solid, it refers to a state where the elements share electrons in a vast three-dimensional network. This structure gives metals their characteristic properties, such as electrical conductivity and malleability.
Interestingly, iodine ( I_{2} ) is a nonmetal that exhibits metallic characteristics under certain conditions, referred to as a metallic solid. It crystallizes in a way that allows it to conduct some electricity, and it has a shiny, metallic luster when pure.

• This dual nature makes iodine unique among halogens.
• Metallic iodine can demonstrate properties common to metals while being primarily a nonmetal element.

Understanding how elements like iodine can exhibit properties of both metals and nonmetals broadens our view on element classification, illustrating the gradients and overlaps between categories of the periodic table.