Teach a Pokemon mud slap or something along the lines of that
Rock Smash will be super effective against Magnemite but not Voltorb. The reason for this is because Magnemite is an Electric and Steel type pokemon and Fighting type moves like Rock Smash are super effective on Steel. Voltorb is just an Electric type, therefore Rock Smash will not have a type advantage nor disadvantage.
almost all of them a good pokemon to train is gabite.
Lightning is super effective against water. I hope this helps.
Flying and Psychic are super effective against fighting
Ghost & Flying. I believe that's it! Not dark or bug because although they're super-effective against Psychic, they are not-effective against Fighting. And not Psychic, because though it's super-effective against Fighting, it's not-effective against Psychic.
Water and Grass attacks are super effective against Onix.
psychic pokemons and attacks are super effective
super effective is bug
Bug Type and Fighting Type moves are super effective against it.
Rock, electric, ice, and psychic types are super effective against Crobat.
Steel is super effective against rock type pokemon.
normal type Pokemon are not super effective against any type.