1. The number of atoms in a mole of any pure substance is called Avogadro's Constant (6.022 x 10^ 23)
2. As the masses of the elements in the periodic table increase, the numbers of atoms in 1 mol of each element remains the same.
3. If samples of two different elements each represent one mol, then they contain the same number of atoms.
4. Any Avogadro's Constant amount of any element is equivalent to 6.022 x 10^23 particles.
5. The molar mass of an element is the mass of one mole of the element.
6. The atomic mass of Hydrogen is 1.008 amu. The reason that this value is not a whole number, is that Hydrogen has more than one isotope.
7. A chemical formula includes the symbols of the element's in the compound and subscripts that indicate how many atoms or ions of each type are combined in the simplest unit.
8. Changing a subscript in a correctly written chemical formula changes the formula so that it no longer represents that compound.
9. A formula that shows the simplest whole-number ratio of the atoms in a compound, is the empirical formula.
10. The empirical formula is always the accepted formula for an ionic compound.
11. The empirical formula for a compound shows the symbols of the elements with subscripts indicating the smallest whole-number ratio of the atoms.
12. The empirical formula may not represent the actual composition of a unit of a molecular compound.