Periodicity study guide

Study Guide for Periodicity

This study guide covers essential concepts related to periodicity that are crucial for A-Level Chemistry.

Key Concepts

• Block Classification: Understand how to classify elements as s, p, d, or f block based on their electron configurations and position in the periodic table.
• Proton Number: Recognize that the atomic number determines the position of an element in the periodic table and influences its chemical properties.

Trends in Period 3

1. Atomic Radius:

• Trend: Decreases from sodium to chlorine.
• Reason: Increased nuclear charge pulls electrons closer to the nucleus.

1. First Ionisation Energy:

• Trend: Increases across the period.
• Reason: Higher nuclear charge makes it harder to remove an electron.

1. Melting Points:

• Trend: Varies significantly; metals have high melting points while non-metals have lower.
• Reason: Differences in bonding types (metallic vs. covalent).

Application of Data

• Use periodic trends to predict the behavior of elements in reactions. For example, elements with low ionisation energies are more likely to form cations.
• Justify your explanations with data from the periodic table, such as comparing ionisation energies or atomic radii.