Define Oxidation and reduction in terms of electron transfer.

This is the most commonly used definition of oxidation and reduction and most widely applicable.

In this case, Oxidation is the loss of electrons and Reduction is the gain of electrons.

A very clever mnemonic to remember this concept is oil rig.

OIL RIG

Oxidation is loss Reduction is gain

Explanation:

Have a  great day

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

i do not get it   at all