This definitions covers Key Definitions within Electronic Configuration for GCSE Chemistry. Revise Electronic Configuration in Atomic Structure for GCSE Chemistry with 24 exam-style questions and 24 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 7 of 12 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
📖 Key Definitions
Electron shell (energy level): A region around the nucleus where electrons are found, each shell holding a maximum number of electrons (2, 8, 8...).
Electronic configuration: The arrangement of electrons in shells around the nucleus, written as numbers separated by commas, e.g., 2,8,1.
Outer shell electrons (valence electrons): The electrons in the outermost occupied shell — these determine the chemical properties and reactivity of an atom.
Period: A horizontal row in the periodic table; the period number equals the number of occupied electron shells.
Group: A vertical column in the periodic table; the group number equals the number of electrons in the outer shell.
Practice questions for Electronic Configuration
What is the maximum number of electrons the first electron shell can hold?
Explain why noble gases are unreactive.