Matter 3-3 ELEMENTS

Pure Substance All particles (atoms or molecules) are alike Elements are the simplest pure substance.

Atoms The smallest particle of an element that has all the properties of that element Atoms of the same element are identical to each other.

a short way or writing an element One or two letters The first is capital; the second is lowercase Chemical Symbol

Some come from the current name of the element Some come from older Latin or Greek names Where do elements’symbols come from?

Matter 3-4 COMPOUNDS

Compound Pure substance made of two or elements bonded together chemically New, different properties than the elements that make it up. Can be separated into the original elements, but needs heat, electricity, or another chemical reaction.

Molecule Smallest particle of a compound Two or more atoms chemically bonded All molecules of the same compound are the same.

Chemical Formulas Element symbols together to represent a compound or molecule. Subscript tells how many of each atom

Chemical Equations Chemical formulas that show a reaction. Reactants  products Must be balanced so that same number of each atom is on each side

Coefficient Number used to balance a chemical equation