Answer:
Lithium and sodium are the most similar because they are both alkali elements located in the same group, and therefore have similar properties.
Nitrogen and oxygen are not the most similar because although they are both non metals elements, are each located in a different group
Explanation:
Li and Na are both alkali elements from group 1 that shares some similities. The both can be obtained by the water hydrolysis. These are common reactions:
Metal from group 1 + H₂O → Base + H₂
Metal from group 1 + O₂ → oxides
Metal from group 1 + group 17 → ionic halides
Both form cations with 1+ charge, they can release only 1 e-
N is an element from group 15 and O, from group 16. They are both non metal.
Nitrogen can make a variety of oxides.
They react in water to produce nitric acid:
N₂O₃ + H₂O → 2HNO₃
N₂O₅ + H₂O → 2HNO₃
It has an anion with -3, as oxidation state. (Nitride)
The N with H, makes a well known hidride → ammonia
N₂ + 3H₂ → 2NH₃
The Oxygen also makes a well known hidride → water
2H₂ + O₂ → 2H₂O
Both are covalent hidrides.
N can have many oxidation's states. O always acts with -2 except for the peroxydes, with -1. O can have a great power of oxidation, that N does not have.
O₂ always acts as a reactant, at combustion reactions.
