This key facts covers Isotopes within Atomic Structure for GCSE Physics. Revise Atomic Structure in Atomic Structure for GCSE Physics with 16 exam-style questions and 25 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 5 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
🔄 Isotopes
Definition: Isotopes are atoms of the same element (same number of protons) with different numbers of neutrons.
Examples — Carbon isotopes:
| Isotope | Protons | Neutrons | Stable? |
|---|---|---|---|
| Carbon-12 | 6 | 6 | Yes (99%) |
| Carbon-13 | 6 | 7 | Yes (1%) |
| Carbon-14 | 6 | 8 | No (radioactive) |
Key points:
- Same chemical properties (same electrons)
- Different physical properties (different mass)
- Some isotopes are radioactive (unstable nucleus)
Practice questions for Atomic Structure
What does the atomic number of an element tell you?
Describe the structure of an atom. Include the location and charge of the three main subatomic particles.
Quick recall flashcards
What are isotopes?
Isotopes are atoms of the same element (same number of protons) with different numbers of neutrons. This means they have the same atomic number but different mass numbers.
Why are atoms electrically neutral?
Atoms are electrically neutral because the number of protons (positive charges) equals the number of electrons (negative charges). The positive and negative charges cancel out.