Classify the following elements based on their periodic properties: Sodium (Na), Chlorine (Cl), Magnesium (Mg), and Argon (Ar). Which category do they belong to based on their metallic character?

Sodium, magnesium, chlorine, and argon can be grouped by how metallic they are. Sodium and magnesium are metals, so they have strong metallic character: they lose electrons easily, form positive ions, and conduct heat and electricity. Chlorine and argon are non‑metals; chlorine is a halogen that readily gains electrons to form chloride ions, while argon is a noble gas that is completely inert and does not ionize. Thus, sodium and magnesium belong to the metallic category, whereas chlorine and argon belong to the non‑metallic category. This classification follows the trend that metals are found on the left side of the periodic table and non‑metals on the right.