Detect empty input arg in bash script

Question

I have a script that has a given number of input variables. I would like to detect if all of the variables have been given and quit otherwise. For example lets say the script has 10 input args but only 6 are given. Then I would like to quit. I tried

arg1=$1
arg2=$2
...
arg10=$10
for i in $(eval echo {$1..$10}); do
   echo "$i"
   if [[ -z "$i" ]]; then
       echo 'wrong number of args'
       exit 2
   fi
done

The echo inside the loop (echo "$i$") prints out but the loop always exits. So I have some basic flaw.