What is a characteristic of the chemical properties of alkenes?

Alkenes are indeed characterized as unsaturated hydrocarbons, which means they contain at least one double bond between carbon atoms. This double bond significantly affects their chemical properties, making them more reactive compared to alkanes (which are saturated). The presence of the double bond allows alkenes to participate in various chemical reactions, such as addition reactions where other atoms or groups can add across the double bond, leading to the formation of saturated compounds.

This reactivity due to the double bond distinguishes alkenes from alkanes, which are much less reactive. Their ability to undergo reactions with a variety of reagents, including halogens, hydrogen, and acids, highlights the unsaturation in their structure, proving they are not just reactive but significantly more so compared to saturated hydrocarbons. Thus, recognizing that alkenes are classified as unsaturated compounds underscores their characteristic as being highly reactive in chemical contexts.