Magnesium belongs to which of the following groups? 

Alkaline earth metals 

The correct answer is option 1. Alkaline earth metals.

The periodic table is organized into groups and periods. Groups are vertical columns, and elements within the same group share similar chemical properties due to similarities in their electron configurations.

Magnesium (Mg) belongs to Group 2 of the periodic table, also known as the alkaline earth metals group. This group includes beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).

Alkaline earth metals have some distinctive characteristics:

1. Valence Electrons: Elements in the alkaline earth metals group have two valence electrons in their outermost energy level (shell), which makes them highly reactive, though less so than the alkali metals in Group 1.

2. Reactivity: Alkaline earth metals are less reactive than alkali metals but still readily react with nonmetals to form compounds. For example, magnesium readily reacts with oxygen to form magnesium oxide.

3. Metallic Properties: Like all metals, alkaline earth metals are shiny, malleable, and good conductors of electricity.

4. Ionization: They tend to lose two electrons to form divalent cations with a +2 charge.

Magnesium, specifically, is a lightweight, silvery-white metal. It is commonly found in minerals such as magnesite and dolomite. Magnesium and its compounds have various applications, including in alloys, in the production of magnesium oxide (used in refractory materials), and in biomedical applications due to its role in biochemical processes.

Overall, alkaline earth metals, including magnesium, play essential roles in both industrial and biological processes, owing to their unique chemical properties.