Physical Science Vocabulary

Atom: The smallest part of matter.
Element: Atoms of 1 type.
Compound: 2 or more different elements chemically combined.
Molecule: 2 or more atoms combined together.
Pure Substance: A substance that has the same chemical makeup; can be an element or compound.

Nucleus: The center of the atom.
Proton: Subatomic particle with a positive charge; located in the nucleus.
Neutron: Subatomic particle that is neutral or has no charge.
Electron: Subatomic particle with negative charge; located outside the nucleus.
Valence Electrons: Outer shell electrons.

Periodic Table: A table of known elements arranged by atomic number.
Atomic Number: The number of protons/electrons in an atom; usually located at the top of an element tile.
Atomic Mass: The number of protons + neutrons in the nucleus ( $\text{Atomic Mass} = \text{Protons} + \text{Neutrons}$ ); usually located on the bottom of the element tile.
Symbol: The 1-2 letter abbreviation representing the element, usually found in the center of the elemental tile.
Group / Family: The vertical column in the periodic table.
Period: The horizontal row on the periodic table.
Metals: An element that is shiny, malleable, and a good conductor of electricity; located to the left of the zig-zag line on the periodic table.
Nonmetals: An element that is brittle, dull, and a bad conductor of electricity; located to the right of the zig-zag line on the periodic table.
Metalloid: An element that has the characteristics of both metal and nonmetals; located on the zig-zag line of the periodic table.

Mixture: 2 or more elements and/or compounds physically combined.
Homogeneous Mixture: A mixture that looks the same throughout; cannot see the different pieces in the mixture.
Heterogeneous Mixture: A mixture that looks different and all the parts of the mixture are visible.

Reactants: The starting substances in a reaction.
Products: The ending substances in a reaction.
Law of Conservation of Mass: States that matter/mass cannot be created or destroyed.