Nice try, but:

1) Tenacity does not stack. So Eleisa's Miracle isn't needed when u got Mercury's Treads...
2) Sth wrong with ability Sequence, Masteries and Runes - write about other choices, really increase q and w before e?
3) You need to improve your build, check jhoijhoi's guide how to make a guide.

This isn't finished and the items are kinda weird...

Core items are:
Shureyla's
Randuins
Tri-F


You don't need madreds as that is a highly situational item for if the other team has like mundo, voli, sej, that all stack hp and madreds most certainly doesn't belong on skarner that is suppose to be a tank. Elise's pendent of w.e is terribad item....regen isn't that useful in fights unless you are Mundo and this make u miss key item.

Your core items are there because. Tri-F for constant procs, slow, MS. Randuins for active. And shureyla's for that boost of speed to catch your enemy in ur ultimate.

Personally when I jungle with skarner I like to get my Trinity force much earlier than as my last item. It's a big help for getting more damage on those ganks and you don't need to get those tanky items as fast because skarner wins almost every 1v1 he's in.