Counting atoms examples

Step 1

Locate the elements in the chemical's molecular formula. These are represented by their symbol. For example, the chemical formula for ammonium phosphate is (NH4)3PO4.

Counting atoms worksheet

Counting atoms answer key

Counting atoms with parentheses

How to find the number of atoms in an element

Counting atoms calculator

The elements in this compound are nitrogen (N), hydrogen (H), phosphorous (P), and Oxygen (O).

Step 2

Add a subscript one for any element that does not have a subscript number already. In ammonium phosphate, the nitrogen and oxygen have no numerical values.

By convention, no number is added if there is only one atom of the element in the formula. Adding a value of one to these elements will remind you to count them when adding the number of atoms.

Step 3

Add the subscript numbers within any parenthesis.

Then multiply by the value of the subscript located after the closed parenthesis.

Counting atoms and molecules

In ammonium phosphate, the NH4 is enclosed in parenthesis. The sum of the atoms within the parenthesis is five. The number three after the closed parenthesis indicates a total of three ammonium groups within the compound. Since each group has five atoms multiplying three groups by five

how to count atoms in a chemical formula using subscripts and coefficients

how to count atoms in a chemical formula with parentheses