Counting atoms

Front

What is an atom?

Back

The smallest unit of a chemical element, consisting of a nucleus surrounded by electrons.

Front

What is a molecule?

Back

A group of two or more atoms bonded together, representing the smallest fundamental unit of a chemical compound.

Front

How do you determine the number of atoms in a chemical formula?

Back

Count the number of each type of atom indicated by the subscripts in the formula.

Front

What does the subscript in a chemical formula indicate?

Back

The number of atoms of the element that precedes it in the molecule.

Front

What is the chemical formula for water?

Back

H₂O, which indicates 2 hydrogen atoms and 1 oxygen atom.

Front

How many total atoms are in the compound C₃H₈?

Back

11 total atoms (3 carbon, 8 hydrogen).

Front

What is the significance of parentheses in chemical formulas?

Back

Parentheses indicate that the atoms inside are grouped together and can be multiplied by a subscript that follows the parentheses.

Front

How many oxygen atoms are in the compound Al(OH)₃?

Back

3 oxygen atoms (1 from OH multiplied by 3).

Front

What is the total number of atoms in H₂SO₄?

Back

7 total atoms (2 hydrogen, 1 sulfur, 4 oxygen).

Front

How many atoms are in the compound C₂H₄?

Back

6 total atoms (2 carbon, 4 hydrogen).