Hydrogen has how many outer-shell electrons?
Hydrogen has 1 outer shell which contains 1 electron.
As seen by the periodic table Hydrogen has 1 electron, this is evident from the lower number on Hydrogen which tells you how many neutrons and electrons the element has.
If Hydrogen has 1 electron it can only have 1 outer shell (or orbital) as an electron cannot by split across shells.
In general, the first shell can hold 2 electrons, the second can hold 8. Consequently, hydrogen only has 1 outer shell as it has less than 2 electrons so it does not need another shell.