What is the ground-state electron configuration of a neutral atom of hydrogen?
The lowest energy state.
1 electron in the S shell. 1s1 is the common notation, I think.
1 electron in the innermost shell, so configuration of just '1' (or '1s1' if considering orbitals).
Hydrogen in the ground state only has one electron, and since electrons "fill up" from the innermost electron shell/level outward, then this 1 electron is within the innermost shell.
To denote this as an electron configuration (using the 2-8-8 format) :
Considering s, p, d, and f orbitals the electron would likewise fill the s orbital of the first shell, so configuration would be: