Yes, you can position zoom slider
Try the syntax below
var map = new esri.Map("map", {
showAttribution: false,
sliderPosition: "top-right",
sliderStyle: "large"
});
if you put it in the bottom of your webmap page, then, try "bottom-right" or "bottom-left"
Also, you can change the sliderStyle: from "large" to "small"