Study Notes
Atoms are composed of three subatomic particles: protons, neutrons, and electrons. The nucleus of an atom contains protons and neutrons, while electrons orbit in energy levels around the nucleus. Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.
- Atom — the basic unit of an element consisting of protons, neutrons, and electrons. Example: A carbon atom has 6 protons, 6 neutrons, and 6 electrons.
- Proton — a positively charged subatomic particle found in the nucleus. Example: Hydrogen has one proton.
- Neutron — a subatomic particle with no charge found in the nucleus. Example: Carbon-12 has 6 neutrons.
- Electron — a negatively charged subatomic particle orbiting the nucleus. Example: Electrons in a carbon atom orbit in energy levels.
- Isotope — atoms of the same element with different numbers of neutrons. Example: Carbon-12 and Carbon-14 are isotopes of carbon.
Exam Tips
Key Definitions to Remember
- Atom: Basic unit of an element.
- Isotope: Atoms with the same number of protons but different neutrons.
Common Confusions
- Confusing isotopes with ions.
- Misunderstanding the role of neutrons in isotopes.
Typical Exam Questions
- What is an isotope? Atoms of the same element with different numbers of neutrons.
- How do protons and electrons differ? Protons are positively charged, electrons are negatively charged.
- What is the role of neutrons in an atom? Neutrons stabilize the nucleus and contribute to atomic mass.
What Examiners Usually Test
- Understanding of atomic structure.
- Ability to identify isotopes and their properties.