and do u think that would take care of the inmunes?
If you're unlucky enough to get a phys/cold immune monster and you're by yourself, just s/e and make a new game or move on. It probably isn't worth your time to spam lightning all day until you finally kill it.
take a look at d2skills.com
with 1 into charged bolt, 20 into lightning and 9 into mastery (30 points) AND with 15 all/sorc skills, you'll be pumping out a sad 4-3367 damage.
with 1 point into cb, 1 into lightning, 1 into chain, 1 into static (probably should have already), 1 into nova for prereqs. you will end up with the best possible damage with 15 storm and 10 mastery AND with 15 all/sorc skills, giving you 1335-1769.
Now, this may not seem like much, but you will probably never run into a cold AND phys immune monster that will hinder progress. With this in mind, you will be doing an extra 1500~ damage to a random monster all the time.