Both are different. Combining capacity of an element or a radical with another element or radical to form a compound or molecule is known as valency and whereas radicals are charged atoms or group of atoms having a common charge which act as a single unit during a chemical reaction and highly reactive & unstable chemical species. To calculate the charge of an ion, The atomic number of the ion will be equal the number of protons in it. If an ion loss two electrons then it’s charging is +2. If the atom receives an electron then it’s charge is -1. Generally Groups IA, IIA and IIIA all lose electrons and become positively charged. Groups VA, VIA and VIIA all gain electrons and become negatively charged.