Chlorine, fluorine and iodine are examples of known. A. inert gas B. ketone C. halogen D. alkane

The correct answer is: C. halogen

Chlorine, fluorine, and iodine are all halogens. Halogens are a group of elements in the periodic table that are highly reactive and form salts with metals. They are also known as the “salt-forming elements”.

The other options are incorrect.

• Inert gases are elements that have very low chemical reactivity. They are also known as noble gases.
• Ketones are organic compounds that contain a carbonyl group (C=O).
• Alkanes are hydrocarbons that contain only carbon and hydrogen atoms, and are saturated (all bonds are single bonds).