Words of This Topic
- Mass: the amount of material contained in a thing.
- Volume: the amount of room a thing takes up.
- Matter: anything that has both mass and volume.
- Atom: the smallest particle of an element that takes part in a chemical reaction.
- Sub-atomic particles: the proton, the neutron and the electron, which make up an atom.
- Nucleus: the central part of an atom.
- Shell or orbit: the fixed path on which an electron moves.
- Energy level: another name for a shell; K is the first energy level.
- Atomic mass unit (amu): the unit equal to the mass of one proton.
- Atomic number: the number of protons in the nucleus.
- Electron arrangement: the way electrons are shared out among the shells, for example 2.8.6.