What is an isotope?

Answer	Isotopes are atoms of the same element that have different numbers of neutrons. Same protons means same element; different neutrons changes mass. WHY IT MATTERS: Isotopes show up as exam traps and explain why mass can vary without changing the element. AIRCRAFT EXAMPLE: Hydrogen isotopes are a classic example; the element stays hydrogen but mass changes. MEMORY AID: Same P, different N → isotope. EASA TIP: If the question says “same element but different mass,” think isotopes.
Difficulty	Easy
Lesson	2.1.1 Nature of Matter
Module	Module 2.1
Tags	EasyIsotopesModule 2.1