For example, it forms bonds with h. It forms bonds with NA and CA, but it only forms one bond. Now let's look at chlorine. Chlorine is a diatomic gas at room temperature, just like fluorine. Bromine is a diatomic liquid at room temperature, and iodine is a diatomic solid at room temperature. Now, these three guys, chlorine, bromine and iodine, unlike chlorine, can have an oxidation state of up to plus seven, and that means they can all form up to seven bonds. The last important thing you should know about halogens is that halogens can react with the hion.