If you're looking for a double electric attacker just spam eevees until you get a jolteon. This Magneton isn't very useful.
Magneton has a ton of resistances but most aren't relevant because you're probably going to only be using it against Gyarados.
Even if you did have Zap Cannon a Jolteon's still better because of it's stats and it's charge moves have lower duration than Zap Cannon which is important if you need to dodge every attack.
