Periodicity and atomic trends form fundamental concepts in A-level chemistry, particularly when studying electron configurations and chemical properties.
The study of First ionisation energy shows clear patterns across the periodic table, increasing from left to right across a period due to increasing nuclear charge and decreasing atomic radius. This trend is crucial for understanding atomic structure and bonding. When examining Successive ionisation energy, students learn how removing subsequent electrons requires progressively more energy, especially when removing electrons from inner shells. This is particularly evident in elements like sodium, where the Successive ionisation energy of sodium shows dramatic increases after the first electron is removed.
Group 7 elements, also known as halogens, demonstrate key periodic trends that are essential for A-level understanding. Their reactivity decreases down the group as atomic radius increases and electron affinity decreases. These elements undergo characteristic displacement reactions where a more reactive halogen can displace a less reactive one from its compounds. The trend in atomic radius increases down the group due to additional electron shells, while electronegativity decreases. This knowledge is crucial for understanding both theoretical concepts and practical applications in chemistry. Students must also grasp how these trends relate to electron configurations and chemical bonding, particularly in redox reactions involving halogens. The relationship between atomic structure and chemical properties becomes evident when studying the Trend in second ionisation energy across period 3, which shows variations based on electron configurations and nuclear charge. Understanding these patterns helps predict chemical behavior and explains why certain elements react the way they do, making it an essential topic for both theoretical knowledge and practical applications in chemistry examinations.
