If you cross white leghorn rooster with rhode island red hen will the chicks be sex links or mixed?

NO, neither breed is sexlinked. What you need to do is breed a Rhode Island Red or New Hampshire rooster with a Barred Rock(Black Stars) or Rhode Island Red or New Hampshire rooster and a Silver Laced Wyandotte, Rhode Island White or Delaware hen(all Red Stars) and you will get sexlinked chicks. The chicks that hatch out solid black are pullets(hens) and the chicks that hatch out black but with a large yellow dot on top of their heads are cockerels(males).

This answer is wrong. The rooster has to be the Rhode Island Red and the hen the White Leghorn. The pullets will have reddish fluff and the males will have yellow fluff leading to white feathers.