question about exit command

[ali hagigat]

I have two script files and I execute them as follows:
-------------------------------------
#script1
echo ppp
exit 0
echo qqq
/root> ./script1
ppp
-------------------------------------
#script2
if (exit 0) then
    echo ppp
fi
/root> ./script2
ppp
-------------------------------------
In script1, when exit executes, it returns and immediately
shell(/bin/bash) returns too. Why in the second script shell completes
if command and does not return immediately? In script 2, what will be
the return value of shell? The option of exit or the return value of
echo?