This key facts covers Trends in the Periodic Table within The Periodic Table for GCSE Chemistry. Revise The Periodic Table in Atomic Structure for GCSE Chemistry with 20 exam-style questions and 24 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 6 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 6 of 12
Practice
20 questions
Recall
24 flashcards
📈 Trends in the Periodic Table
Down a group:
- Atomic radius increases (more electron shells)
- Group 1 reactivity INCREASES (outer electron further from nucleus, easier to lose)
- Group 7 reactivity DECREASES (harder to attract an electron into a larger atom)
- Melting/boiling points — trend varies by group
Across a period (left to right):
- Atomic radius decreases (more protons pull electrons closer)
- Metallic character decreases (metals → non-metals)
- Elements go from highly reactive metals → non-metals → noble gas
Quick Check: An element is in Group 2, Period 3. How many outer electrons does it have and how many electron shells?
2 outer electrons (Group 2) and 3 electron shells (Period 3). This is magnesium, with electronic configuration 2,8,2.