Atomos is an ancient Greek word meaning 'indivisible' or 'cannot be cut'. Atoms are the building blocks of matter; they are the smallest particles that when combined together have the properties of a particular chemical element, or compound.
Electron configuration
The electron configuration, that is the distribution or arrangement of electrons in the atom, can be described by the Bohr model of the atom and the quantum mechanical model of the atom.
Electrons in atoms
First ionisation energies provide evidence for our quantum mechanical model of the atom. The language here is very important, using the specific terms (e.g. orbital, sub-level etc.) correctly will get you the marks in the exams.
The nuclear atom
This section is the foundation of atomic structure and explains the numerical values given on the periodic table.