Salamence is a Dragon and Flying-type and because of which its weaknesses are Rock, Ice and Dragon prior to Pokemon X and Y however Fairy-types were added as a weakness for Salamence as of X and Y.
Being a dragon/flying type, like dragonite, Salamence is 4 times weak against Ice type moves. Dragon type moves are also super-effective but only by x2.
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.
super effective is bug
psychic pokemons and attacks are super effective
Salamence is weak against Ice (4x the damage), Fairy, Rock, and Dragon-type attacks.
Any Pokemon that knows a rock, dragon, or ice move. Those are the things Salamence is super effective against.
Being a dragon/flying type, like dragonite, Salamence is 4 times weak against Ice type moves. Dragon type moves are also super-effective but only by x2.
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.