Electric would actually be the deadliest.
In terms of how our reality is, yes. But your not having Pokemon come to our universe with the same laws of physics. You are going to the world of Pokemon where these things are equally powerful and physics works differently. Electricity is constantly shown in the anime as not being as powerful as it is in our world. Things get zapped all the time and they just flinch or get hurt. In our world they would be temporarily paralyzed for quite awhile, and that's just at low voltage (The move Thunderbolt would kill most things in our world). Don't think about how our world would be with Pokemon, it wouldn't work. You are going to their world where physics works slightly differently.
So in terms of the Pokemon world, I think you mean Rock and Ground would be your biggest weakness. Rock Pokemon don't get much love but they are very good actually. For example, Charizard would get 1 shoted by a single Rock Blast. It may not make sense for how things work in our world, but they do work in Pokemon world, whether it makes sense to us or not.