Introduction
Atoms are the smallest building blocks of matter. There are about 100 naturally occurring types of atom. This chapter explains the ways in which atoms differ from one another.
Structure 1.2.1 - Atoms contain a positively charged, dense nucleus composed of protons and neutrons (nucleons). Negatively charged electrons occupy the space outside the nucleus.
- Use the nuclear symbol ZXA to deduce the number of protons, neutrons and electrons in atoms and ions.
Guidance
- Relative masses and charges of the subatomic particles should be known; actual values are given in the data booklet. The mass of the electron can be considered negligible.
Tools and links
- Structure 1.3 - What determines the different chemical properties of atoms?
- Structure 3.1 - How does the atomic number relate to the position of an element in the periodic table?
Structure 1.2.2 - Isotopes are atoms of the same element with different numbers of neutrons.
- Perform calculations involving non-integer relative atomic masses and abundance of isotopes from given data.
Guidance
- Differences in the physical properties of isotopes should be understood.
- Specific examples of isotopes need not be learned.
Tools and links
- Nature of science, Reactivity 3.4 - How can isotope tracers provide evidence for a reaction mechanism?
Structure 1.2.3 - Mass spectra are used to determine the relative atomic masses of elements from their isotopic composition. (HL)
- Interpret mass spectra in terms of identity and relative abundance of isotopes.
Guidance
- The operational details of the mass spectrometer will not be assessed.
Tools and links
- Structure 3.2 - How does the fragmentation pattern of a compound in the mass spectrometer help in the determination of its structure?
Structure 1.2 - The nuclear atom