Calculate Average Atomic Mass From Isotopes

Start with the valence electron table so students see the group patterns, then move to the trend graphs. Use the review quiz to close the unit.

Calculate average atomic mass from isotope percents for gallium, boron, copper and magnesium. The directions on the page read: Use mass numbers to find each average atomic mass to 2 decimal places and compare it with the tile. Then answer the questions. An answer key is included.

Yes, both. We made it for 8th grade matter, and it works the same at home or at school. At home, a student can work through it alone and then go over it with you, which shows quickly what is solid and what needs another look. In class it works as independent practice, homework or a warm-up, and you can print one copy or a full set.

Ordering by mass would put potassium before argon, but potassium is a reactive metal like sodium and argon is an unreactive gas like neon. Atomic number keeps similar elements in the same group. Graph Atomic Mass Against Atomic Number explores this.

Groups 1, 2 and 13 lose 1, 2 or 3 electrons and form positive ions. Groups 15, 16 and 17 gain 3, 2 or 1 electrons and form negative ions. Label Ion Charges and Trends on the Table has students write these on a table.

Name the metal first, then the nonmetal with its ending changed to ide. Sodium and fluorine make sodium fluoride, NaF. Solve Clues to Name Ionic Compounds gives clues by group and period.