Question

Given the redox reaction: Ni + Sn4+ → Ni2+ + Sn2+
Which species has been oxidized?

Answer 1

remember this---> LEO=  lose electons oxidation... and GER----> gain electrons reduction

so if you look for the one being oxidized, it is the one losing electrons. since electrons are negative, when an atom lose them, it becomes less negative, so more positive. 

you can identify the oxidization when the atom becomes more positive.

so in the given reaction: Ni + Sn4+ → Ni2+ + Sn2+

Ni becomes Ni +2   and    Sn+4 becomes Sn+2

as you can see the Ni become Ni+2 so more positive

Ni is being oxidized

Answer 2

Nickel underwent an increase in oxidation number from zero to +2 hence Ni was oxidized.

What is oxidation?

The term oxidation has to  do with an increase in oxidation number. Let us look at the species closely from left to right and determine which specie underwent an increase in oxidation number.

Looking from left to right, we can see that Nickel underwent an increase in oxidation number from zero to +2 hence Ni was oxidized.

Learn more about oxidation number: https://brainly.com/question/15167411