chemical formulas

[Noh_Jasmine_1J]

hi, I can confused on when to use subscripts for certain elements on the periodic table. For example, I don't know understand why chlorine gas is written as Cl2 instead of just Cl (M.15)

[Sarah_Kang_2K]

Cl on its own would refer to the ion form (Cl-). Cl2, along with N2, H2, and O2 are all gaseous forms of the elements.

[Germar G 4F]

There is a list of diatomic elements, which means they get a subscript of 2 every time you write them in a chemical equation. The diatomic elements are Hydrogen, Nitrogen, Fluorine, Oxygen, Iodine, Chlorine, and Bromine. Remember them with this mnemonic:

Have No Fear Of Ice Cold Beer

[Camille Marangi 2E]

Chlorine is a diatomic element. Diatomic elements are pure elements that form molecules consisting of two atoms bonded together because they are extremely unstable alone due to their *almost* full valence shell. There are 7 of these diatomic elements and the easiest way I find to remember them is to use the mnemonic device Dr. Brinclhof (Br I N Cl H O F) where Br= bromine, I= Iodine, N=nitrogen, Cl=chlorine, H-hydrogen, O=oxygen, and F=fluorine

[Arshia Ramesh 1G]

BrINClHOF