Took the trouble to look it up for you:
Samsung QE55Q7F (55", 4K, One Connect Box, QLED, LCD)
It says "VESA wall mount type 400 x 400 mm", like most mid-sized TVs I know.
And here with the bracket it says "VESA wall mount type
300 x 300 mm , 600 x 400 mm , 200 x 200 mm , 400 x 400 mm , 400 x 200 mm , 400 x 300 mm , 300 x 200 mm , 600 x 300 mm , 500 x 400 mm".
MfG
