Study Notes
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons, resulting in different mass numbers. Despite these differences, isotopes have identical chemical properties because they have the same electronic configuration.
- Isotope — 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. - Relative Atomic Mass (Ar) — the average mass of an element's isotopes compared to 1/12th of the mass of a carbon-12 atom.
Example: Chlorine has a relative atomic mass of 35.5 calculated from its isotopes.
Exam Tips
Key Definitions to Remember
- Isotopes: Atoms with the same number of protons but different numbers of neutrons.
- Relative Atomic Mass (Ar): The average mass of an element's isotopes compared to 1/12th of the mass of a carbon-12 atom.
Common Confusions
- Confusing atomic number with mass number.
- Assuming isotopes have different chemical properties.
Typical Exam Questions
- What are isotopes?
Atoms of the same element with different numbers of neutrons. - How do you calculate relative atomic mass?
By averaging the masses of an element's isotopes based on their abundances. - Why do isotopes have the same chemical properties?
Because they have the same number of electrons and electronic configuration.
What Examiners Usually Test
- Understanding of isotopes and their properties.
- Ability to calculate relative atomic mass from isotopic data.
- Knowledge of the relationship between atomic structure and chemical properties.