Oxidation number?

[Brianna Brockman 1F]

Professor Lavelle briefly mentioned in lecture about knowing the oxidation number based on an element's location on the periodic table? What was he referring to? I never learned that in high school.

[Rachel-Weisz3C]

There are some rules that are helpful to identify an elements oxidations number, based on there location in the periodic table. For example, if the element is in group 1, its oxidation number is always +1. Likewise, if it is in group 2, the oxidation number is always +2.

[Amar Singh]

Group 1 elements have +1. Group 2 elements have +2. Group 17 have -1. Group 16 have -2. The others can vary a bit depending on the element and its state.

[Sean Reyes 1J]

Usually, you can find the oxidation numbers of an element in a compound by using the oxidation numbers of the other elements present in that same compound. For example, in MnO4-, you know that the oxidation number of oxygen is -2. Using that information, you can find the oxidation state of the manganese.
There are other rules too, such as the location on the periodic table, with Group 1 having a +1 charge, Group 2 having a +2 charge, Group 16 having a -2 charge (with the exception of oxygen in a peroxide), and Group 17 having a -1 charge.

[404982241]

We always know that oxygen has a -2 charge and hydrogen always has a +1 charge. Regarding electrochemistry, this is important because if we are given a molecule like XO2H2 with no charge where X is an imaginary atom, we know that X must have an oxidation number of +2

[Amy Dinh 1A]

Group 1 (alkali metals) elements will always have a +1 charge, Group 2 has a +2 charge, group 7 has a -1 charge.

[Abby-Hile-1F]

I know there are some exceptions to this, but how do you know if an element in a particular atom has a different oxidation number than usual (the one indicated by position in the periodic table?

[jlinwashington1B]

He is referring to the groups and their charges on the periodic table.

[I am Sodium Funny]

If you follow along the columns of the periodic table then you can see the pattern of oxidation numbers. (E.g. row 17 species oxidation # is -1)

[Jayasuriya Senthilvelan 4I]

It's basically the idea that the group that an element is found can give clues as to what its oxidation number if. Note, that this doesn't work for transition metals. Example: elements in group 1 have an oxidation number of +1 and elements in group 2 have an oxidation number of +2. Elements in the second to last group (halogens) have an oxidation number of -1.

[Catly Do 2E]

This list really helped me determined oxidation numbers!

[Tony Chung 2I]

There are certain elements that have specific charges. You need to know these to properly balance the redox equation.

[Alysa Rallistan 2G]

Once you get the hang of what oxidation numbers belong to certain elements, then you can use those to calculate the unknown oxidation numbers of other elements. To do this you must match the overall charge of the substance with the unknown element