A scorpions venom has no effect on the scorpion or any other scorpion of the same family. However, if the venom is injected directly into the scorpions nerve ganglion(which would be quite an unlikely event outside the laboratory) , the the intoxins in the venom will come into play, and could possibly kill the scorpion within minutes.
2nd answer : Yes, any scorpion can kill another one (same species or not) A scorpion is immune to ITS OWN venom except if it is injected directly in its nervous ganglion and is not immune to the venom of other scorps. (same species or not). They can as well be killed by crushing and dismembering. Emps are said to be the most social scorpions but from time to time they will munch on each other due to dominance, size, overcrowding...
They are predators.