Final answer:
Hydrogen is in Group 1 because it has one valence electron, akin to the alkali metals. Despite its placement, hydrogen is a nonmetal and has a unique ability to lose, gain, or share an electron, distinguishing it from the Group 1 metals.
Step-by-step explanation:
Hydrogen is placed in Group 1 of the periodic table, which is also known as the alkali metals group. However, it is not included as an alkali metal because hydrogen is a nonmetal with properties that differ significantly from those of alkali metals. The reason hydrogen is in Group 1 is that it has one valence electron, like the other alkali metals. Hydrogen's electronic structure consists of a single electron in the 1s orbital, making it similar to Group 1 elements which all have one electron in their outermost s-orbital. Nevertheless, hydrogen is unique because it can lose its electron to form H+, much like the alkali metals, but it can also gain an electron to form H- or share an electron to form a covalent bond, which alkali metals do not.