Oxidation number Periodic Table Oxidation number: related to an atoms valence electrons Highest possible oxidation number of its valence electrons LoWest possible oxidation number #f of electrons needed to gain for an octet Example: C(Group IVA:+4, -4): N(Group VA: +5, -3) s( GroupⅥA:+6,-2);Cl( GroupⅦA:+7,-1) 4Oxidation Number & Periodic Table z Oxidation number: related to an atom’s valence electrons „ Highest possible oxidation number: Highest possible oxidation number: = # of its valence electrons „ Lowest possible oxidation number: = # of electrons needed to gain for an octet z Example: „ C (Group IVA: +4, -4); N (Group VA: +5, -3); S (Group VIA: +6, -2); Cl (Group VIIA: +7, -1). 4