Atomic Structure

This chapter outlines the origins of matter, starting with the Big Bang, an event which produced fundamental particles. As the universe cooled, these particles combined to form atomic nuclei via the strong force, while the electromagnetic force bound electrons to nuclei, leading to the formation of atoms. Hydrogen and helium remain the most abundant elements in the universe, though nuclear reactions have synthesised many others. Atoms are characterised by their atomic number, representing the number of protons in the nucleus, and their mass number, which includes both protons and neutrons. The concept of isotopes, atoms with the same atomic number but different mass numbers, is exemplified using hydrogen's isotopes. Quantum theory is introduced to explain electron configurations, aiding in the understanding of atomic properties like ionisation energy and electronegativity. Lastly, the chapter categorises the subatomic particles relevant to chemistry, discussing their masses, charges, and roles in the formation of elements.