4.7 The Special Names of Elements Present in Various Groups

Elements in the periodic table were given special names based on their physical and chemical properties. Apart from metals, non-metals, and semi-metals, there are also special categories for certain groups of elements.

Alkali Metals (Group-1)

• Elements: Lithium, Sodium, Potassium, Rubidium, Cesium, and Francium (excluding Hydrogen).

• Properties: These elements are highly reactive and are all soluble in water. When dissolved in water, they produce hydrogen gas and form alkali (basic solutions).

• Explanation: They are called “alkali” metals because they form alkaline (basic) solutions when dissolved in water.

Alkaline Earth Metals (Group-2)

• Elements: Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium.

• Properties: These elements occur naturally in various compounds in the soil. They also form alkali when reacting, which is why they are grouped as “alkaline earth metals.”

• Explanation: The term “alkaline” refers to their ability to produce alkali solutions, and “earth” refers to their presence in the earth’s crust.

Coin Metals (Group-11)

• Elements: Copper, Silver, Gold, and Rontzanium.

• Properties: These metals have been historically used to make coins and serve as means of trade and commerce.

• Explanation: The name “coin metals” is derived from their traditional use in coin production.

Halogen Group (Group-17)

• Elements: Fluorine, Chlorine, Bromine, Iodine, Astatine, and Tennessine.

• Meaning of Halogen: “Salt maker” — Halogens form salts when they bond with metals. For example:

• Sodium (Na) + Fluorine (F) = Sodium Fluoride (NaF)

• Sodium (Na) + Chlorine (Cl) = Sodium Chloride (NaCl)

• Properties: Halogens are often found in sea salt and form diatomic molecules (e.g., Cl₂, F₂) by sharing electrons.

• Explanation: The term “halogen” refers to their ability to form salts.

Inert Gases (Group-18)

• Elements: Helium, Neon, Argon, Krypton, Xenon, Radon, and Oganeson.

• Properties: These gases are chemically inert, meaning they do not easily form compounds with other elements. Their outermost energy levels are full, which makes them stable and unreactive.

• Explanation: Because they do not form bonds, they are termed “inert” gases. They remain in gaseous form at normal temperature.

Transition Elements (Groups-3 to 12)

• Properties: Transition elements often form colorful compounds and can act as catalysts in chemical reactions.

• Example: Nickel (Ni), a transition element in Group-10, is used in various organic reactions due to its catalytic properties.

• Explanation: These elements are known for their ability to produce colored compounds and facilitate chemical reactions as catalysts.

Individual Tasks

Problem 1: Why is Calcium (Ca) called an alkaline earth metal?

• Solution: Calcium compounds are found in soil, which categorizes it as an earth metal. Calcium hydroxide (Ca(OH)₂), a compound of calcium, is alkaline in nature, making calcium an alkaline earth metal.

Problem 2: Why is Helium (He) an inert gas?

• Solution: Helium does not bond with other elements and has a full outer electron shell, making it stable and unreactive. Because it does not form compounds or react with other elements, Helium is classified as an inert gas.