tpt Which of the following substances is an element? A. water B. table salt C. iron oxide D. hydrogen

## Step 1<br />An element is a substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom. <br /><br />## Step 2<br />Water (H2O), table salt (NaCl), and iron oxide (Fe2O3) are all compounds, not elements. They are composed of more than one type of atom and can be broken down into simpler substances.<br /><br />## Step 3<br />Hydrogen (H) is an element because it consists of only one type of atom and cannot be broken down into simpler substances.