What is the chemical name for NO2?

The correct name for NO2 is nitrogen dioxide. This compound consists of one nitrogen (N) atom and two oxygen (O) atoms. The naming convention for covalent compounds like this involves using prefixes to indicate the number of each type of atom present. In this case, the prefix "di-" is used for the two oxygen atoms, resulting in "dioxide."

The first part of the name identifies the nitrogen component without a prefix because there is only one nitrogen atom present, thus simply referred to as "nitrogen." Combining these components results in the name "nitrogen dioxide," which accurately reflects the compound's composition.

This approach of using prefixes is essential for clarity in scientific communication, especially with covalent compounds, where multiple atoms of the same element can exist.