A number of transition metals form compounds in the +1 state. Examples being Copper, Gold, Silver and Mercury. Although none of them is too much chemically reactive, yet Copper is tad bit more reactive than the latter two.
Copper would make the most compounds in +1 oxidation state.
+1 in most of the compounds -1 in metal hydrides
The halogens (group 17) have an oxidation number of -1, though the halogens below fluorine can have other oxidation numbers as well. Hydrogen can also have an oxidation number of -1 when it forms hydrides.
There is no compound with the formula CL4. The element chlorine typically forms compounds with a -1 oxidation state, such as in NaCl (sodium chloride).
Hydrogen has an oxidation state of +1 whenever it interacts with a more electronegative element to form a compound (NH3) or whenever it forms an ionic-bonded acid (HClO4) or functions as a cation (NaHCO3). Hydrogen has an oxidation state of 0 in its elemental form. (H2) Hydrogen has an oxidation state of -1 whenever it forms and ionic salt as an anion. (LiH).
An element can have fractional valencies when it forms complex ions or compounds with multiple oxidation states. This occurs when the element shares electrons unevenly or when it exhibits variable oxidation states. For an element to have two integral valence states at the same time, it would need to exist in different chemical environments simultaneously, often in the form of different compounds or complexes exhibiting different oxidation states.
The most common oxidation state of -2 would be Oxygen.
If the question is Cu2, then it is equivalent to Cu and the oxidation number for any element is zero. If the question is Cu2+, then the oxidation number is +2.
uranis has the most compounds
The cation is the metal "Cu", otherwise known as the element Copper.
The two possible oxidation numbers for iron in its compounds are +2 and +3. Iron typically forms compounds in which it loses either two or three electrons, resulting in these two common oxidation states.
The oxidation number for Cl in Cl4 is -1. Since Cl is a halogen, it typically has an oxidation number of -1 when it forms compounds.
The element with nine protons in every atom is fluorine (symbol F). It belongs to the halogen group and is highly reactive. It typically forms a -1 oxidation state in its compounds.