A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Align works on groups of objects, you need more than one object for this. Since, you are having a single chart, hence this option will not get activated.
To experiment. copy and paste the same chart (or create a new chart or create another object like box or picture). Now select both (or more) the charts / objects by holding CTRL and now Align and Group will be activated. The purpose of align is align the selected objects (in your case, it is chart) with respect to each other.