actually,if u want to follow the chromatic scale exactly,u would play this
F chromatic scale,2 octave acceding
E---------------------------------------------------1-
B-----------------------------------------1-2-3-4-5------------
G---------------------------------1-2-3-4----------------------
D-----------------------1-2-3-4-5-----------------------------
A------------1-2-3-4-5--------------------------------------
E--1-2-3-4-5----------------------------------------------
the reason you dont need to fret the fith fret on G is because the fourth fret on g is a b
but dont give up,practice with a metronome on this and good luck