Counting Atoms in a Formula

Start with Atoms, Molecules and Compounds so students have the vocabulary, then label the atom. Use the note on Element Symbols and Names and the box on Counting Atoms in a Formula as references while students work.

Count the atoms of each element in 10 formulas, including coefficients like 3H2O and parentheses. The directions on the page read: Use the box. For each formula, write the elements, the atoms of each element and the total atoms. An answer key is included.

Yes, both. We made it for 6th Grade matter, and the page works the same whether it lands on a kitchen table or a center rotation. At home, most families go through it together and talk the answers out loud, and that talking is where most of the learning happens with atoms and molecules. In class it runs well as independent work while you pull a small group. Print one copy or thirty, whichever the day needs.

An atom is one of the tiny particles all matter is made of. A molecule is a group of two or more atoms held together by chemical bonds. O2 is a molecule with two oxygen atoms.

A small number after a symbol counts the atoms of that element, and no number means one atom. A big number in front multiplies the whole formula, so 2H2O has 4 H and 2 O. Counting Atoms in a Formula also shows how parentheses work.

Protons have a positive charge and neutrons have no charge, and both sit in the nucleus. Electrons have a negative charge and move around outside the nucleus in electron shells. Parts of an Atom has students record this in a table.