Question

Hydrogen has how many outer-shell electrons?

Answer 1

Valence electrons and outer shell electrons are the same. So, to answer this question we should write the electronic configuration of hydrogen and find the number of electrons in the outermost shell.

Complete step by step solution:
H is the symbol of hydrogen. The word hydrogen is derived from " hudrogenes." which means maker of water. It exists as ${{H}_{2}}$ gas and water in nature. It is the first member of the periodic table of elements. The atomic mass of hydrogen is 1.0080g and the atomic number of hydrogen is 1.
Electronic configuration of an atom is the representation of electronic distribution in the atomic orbitals or shell. It is written with reference to Aufbau's principle which gave a standard order of increasing energy of atomic orbital.
Let's write the electronic configuration of hydrogen.
Z = 1
Electronic configuration: $1{{s}^{1}}$
Valence electrons are the electron that is in the outermost shell of an element. The outermost electron at the first place is ready to lose or gain electrons resulting in formation of compounds with other atoms.
As we can conclude from the above discussion that there is only one electron in the outermost shell of hydrogen. The pictorial representation of valence electrons in shells.

Thus, hydrogen has only 1 electron in its outermost shell.

Note: 'Z' is nothing but the atomic number. We know hydrogen is the first member and simplest element in the periodic table. So, we know the atomic number of hydrogen which is 1. Outermost shell is nothing but the valence shell.