Chemistry – The Periodic Table - Arrangement of elements | e-Consult

The elements in the table exhibit properties directly related to their position in the periodic table.

Sodium (Na) is in Group 1, making it an alkali metal. Alkali metals are highly reactive because they readily lose their single valence electron to achieve a stable electron configuration. This makes sodium a strong reducing agent and highly reactive with water and air.

Magnesium (Mg) is in Group 2, making it an alkaline earth metal. Alkaline earth metals are reactive, but less so than alkali metals. They lose two electrons to form a +2 ion. Magnesium is reactive but less so than sodium. It reacts with acids and water, but not as vigorously as sodium.

Chlorine (Cl) is in Group 17, making it a halogen. Halogens are highly reactive non-metals. They gain one electron to achieve a stable electron configuration. Chlorine is a strong oxidizing agent and readily gains an electron from other substances. It is a poisonous gas.

Noble Gases (e.g., Neon (Ne)) are in Group 18. Noble gases are very unreactive because they have a full outer electron shell. They have a stable electron configuration and do not readily gain or lose electrons. This makes them very stable and rarely form chemical bonds. They are often used in lighting because they do not react with the filament.