A F♯ Major (F♯) chord contains the notes F#, C#, A#. It is built from the major formula 1 - 3 - 5, with F# as the root.
Why does F♯ major feel harder than F major?
It is the same shape, so the difficulty is position rather than form. At the 2nd fret the strings sit a little lower and the frets are wider than further up the neck, which asks more of the barring finger than a mid-neck barre does. Most players find the shape easier at the 5th fret and then work it back down.