Study Notes
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons, resulting in different mass numbers.
- Proton Number — the number of protons in the nucleus of an atom Example: Hydrogen has a proton number of 1.
- Nucleon Number — the total number of protons and neutrons in the nucleus of an atom Example: Carbon-12 has a nucleon number of 12.
- Isotopes — atoms of the same element with the same number of protons but different numbers of neutrons Example: Carbon-12 and Carbon-14 are isotopes of carbon.
Exam Tips
Key Definitions to Remember
- Proton Number: Number of protons in the nucleus of an atom.
- Nucleon Number: Total number of protons and neutrons in the nucleus.
- Isotopes: Atoms of the same element with the same number of protons but different numbers of neutrons.
Common Confusions
- Confusing isotopes with ions, which have different numbers of electrons.
- Assuming isotopes have different chemical properties due to different masses.
Typical Exam Questions
- What is an isotope? Atoms of the same element with different numbers of neutrons.
- How do isotopes of the same element differ? They have different numbers of neutrons and different mass numbers.
- Why do isotopes have the same chemical properties? Because they have the same number of protons and electrons.
What Examiners Usually Test
- Understanding of how isotopes differ in physical properties.
- Ability to calculate the number of neutrons using mass number and atomic number.