CaCl₂ is an ionic compound consisting of one calcium ion and two chloride ions; a single calcium ion has a doubly positive charge while a single chloride ion has a single negative charge. So two chloride ions bonded to one calcium ion results in an electrically neutral calcium chloride compound.
In this particular case, an ion is merely an atom with a positive or negative charge. Since there are three ions that comprise CaCl₂, there are three atoms in a single unit of CaCl₂.
Do not confuse the C here for carbon and/or the I for iodine. There is no chemical element whose symbol is “L” (yet).
