(c) Which is most likely to be a gas at room temperature and ordinary atmospheric pressure, F₂, Br₂, K₂O?

Verified step by step guidance

1. Identify the types of substances: \( \text{F}_2 \) and \( \text{Br}_2 \) are diatomic molecules, while \( \text{K}_2\text{O} \) is an ionic compound.
2. Consider the physical states of diatomic molecules: \( \text{F}_2 \) is a halogen gas, \( \text{Br}_2 \) is a liquid at room temperature, and \( \text{K}_2\text{O} \) is a solid.
3. Recall the general trend for halogens: As you move down the group in the periodic table, the boiling points increase, making \( \text{F}_2 \) more likely to be a gas than \( \text{Br}_2 \).
4. Consider the nature of ionic compounds: \( \text{K}_2\text{O} \) is an ionic compound, which typically exists as a solid at room temperature due to strong ionic bonds.
5. Conclude that \( \text{F}_2 \), being a diatomic molecule with a low boiling point, is most likely to be a gas at room temperature and ordinary atmospheric pressure.

Key Concepts

States of Matter

The states of matter—solid, liquid, and gas—are determined by the arrangement and energy of particles. Gases have particles that are far apart and move freely, while solids have closely packed particles that vibrate in place. Understanding these states helps predict which substances will be gaseous at room temperature and pressure.

Molecular Weight and Intermolecular Forces

Molecular weight influences the physical state of a substance. Generally, lighter molecules with weaker intermolecular forces are more likely to be gases at room temperature. For example, fluorine (F2) is a diatomic molecule with a low molecular weight, making it more likely to exist as a gas compared to heavier molecules like bromine (Br2).

Phase Diagrams

Phase diagrams illustrate the states of a substance under varying temperature and pressure conditions. They help determine the phase (solid, liquid, or gas) of a substance at specific conditions. By analyzing the phase behavior of F2, Br2, and K2O, one can predict which is most likely to be a gas at room temperature and ordinary atmospheric pressure.