What s the valancy on hydrogen?

The valency is nearly always +1 but is occasionally -1 and exists in that case as a very strong base. The H+ is a strong acid. The H- is known as hydride but is very unstable and can react with water to produce hydrogen gas and hydroxide.

Also with regards to oxidation numbers, used to track the transfer of electrons in chemical reactions will usually be +1 but also -1 when it is paired with another atom that is less electronegative than itself. The reason behind this is extremely complex and would require many pages of explanation even above uni level but you can probably find that reason online if you really wanted to.

Valency and valency.....

The valency of an element is the maximum number bonds which it can form, and is often related to the number of valence electrons. Technically, an element can have only one valence. The concept of valency has pretty much disappeared and the notion that an element can have more than one valence violates the definition. This why all of that has been put to rest and we use oxidation state instead. Some elements can have more than one oxidation state.

Hydrogen has one valence electron, has a valency of +1 and oxidation states of mostly +1 and occasionally -1.

Hydrogen's valence number is one, because it has only one valence electron and needs only one shared electron to fill its energy levels. This means it can bond with many elements. For example, four hydrogen atoms can bond with a carbon atom, which has four valence electrons, to form methane.

+1