Periodicity
About this topic
This topic focuses on the Periodic Table and the periodic trends in physical and chemical properties of elements, a cornerstone of the Zambian secondary chemistry syllabus. You will study the arrangement of elements into groups and periods, explain trends in atomic radius, ionization energy, and electronegativity across periods and down groups, and investigate the properties of specific groups like halogens and transition metals. Understanding periodicity allows you to predict element behavior and is fundamental to explaining chemical bonding and reactivity. ECZ exams frequently test knowledge of group properties and the interpretation of trends. This competence is vital for a deep understanding of inorganic chemistry and exam success.
What you'll practise (3 questions)
- Sulphur and selenium are all in the same group of the Periodic Table. From this we would expect selenium to form compounds having the formula... A) SeO₂, Na₂Se and Na₂SeO₃ B) Se₂O, Na₂Se and NaSeO₄ C) SeO₂, Na₂Se and NaSeO₄ D) SeO₃, NaSe and NaSeO₃
- Selenium, Se, is in the same Group of the Periodic Table as sulphur. What is the formula of sodium selenide?
- Sulphur and selenium are in the same group of the Periodic Table. From this, we would expect selenium to form compounds having the formula:
Answer each question above to see the correct answer and a full explanation.