Counting atoms

Front

What is an atom?

Back

An atom is the smallest unit of matter that retains the properties of an element.

Front

What is a molecule?

Back

A molecule is a group of two or more atoms bonded together.

Front

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

Back

Add the subscripts of each element in the formula. If there is no subscript, it is assumed to be 1.

Front

In the formula ClN₆Fe₂, how many total atoms are there?

Back

9 (1 Cl + 6 N + 2 Fe = 9 total atoms).

Front

What does the subscript in a chemical formula indicate?

Back

The subscript indicates the number of atoms of that element in the molecule.

Front

How many atoms are in H₂SO₄?

Back

7 (2 H + 1 S + 4 O = 7 total atoms).

Front

What is the significance of parentheses in chemical formulas?

Back

Parentheses indicate that the enclosed group of atoms is a subunit that can be multiplied by a coefficient.

Front

In the formula 3(NH₄)₂CrO₄, how many hydrogen atoms are there?

Back

24 (3 x 2 x 4 = 24 H atoms).

Front

How many different elements are in C₆H₁₂O₆?

Back

3 (Carbon, Hydrogen, and Oxygen).

Front

What is a coefficient in a chemical formula?

Back

A coefficient indicates how many molecules or units of the compound are present.