Atomic Structure and Properties

1.3 Elemental Composition of Pure Substances

Essential Knowledge:

*These are taken directly from College Board

◼ Some pure substances are composed of individual molecules, while others consist of atoms or ions held together in fixed proportions as described by a formula unit. (SPQ-2.A.1)

◼ According to the law of definite proportions, the ratio of the masses of the constituent elements in any pure sample of that compound is always the same. (SPQ-2.A.2) 

◼ The chemical formula that lists the lowest whole number ratio of atoms of the elements in a compound is the empirical formula. (SPQ-2.A.3)