Did you actually put the exact command that you've shown in to your command block?
If so, take out the ''minecraft:" before the execute. Also, what is that weird symbol on your scoreboard? That may prevent something, just to say. your command should look something like this once you've fixed it.
This strikes all entities within 5 blocks of a snowball with lightning, except for the snowball itself. I want to select which snowballs by their name also so that there can be different types of grenades, all determined by name. For example, this one could be called "Lightning Grenade" and then another could be called "Explosive Grenade" which summons exploding creepers like the lightning. I tried doing the following...
i used 2 commands:
/execute @e[type=Endermite,name=SpawnEnderDragon] ~ ~ ~ kill @e[type=Endermite,r=1]
/execute @e[type=Endermite,name=SpawnEnderDragon] ~ ~3 ~ summon EnderDragon ~ ~ ~
but when i spawn in a endermite named that it doesnt do anything.
Reverse the order you are executing the commands. You cannot target a dead entity. Also, you don't need to /execute to kill the endermite, just use: /kill @e[type=Endermite,name=SpawnEnderDragon]