Question

Classify each of the following as an alkali metal, alkaline carth metal, transition element, halogen, or noble gas: a. \(\mathrm{Ca}\) b. Fe c. Xe d. \(\mathrm{K}\) e. \(\underline{C l}\)

Short answer

Ca: alkaline earth metal; Fe: transition element; Xe: noble gas; K: alkali metal; Cl: halogen.

Step-by-step solution

- Element \(\mathrm{Ca}\text{)

\(\mathrm{Ca}\) is the symbol for Calcium. Calcium belongs to Group 2 of the periodic table, which is classified as an alkaline earth metal.

- Element Fe

Fe is the symbol for Iron. Iron is located in the center of the periodic table, classified as a transition element.

- Element Xe

Xe is the symbol for Xenon. Xenon belongs to Group 18, classified as a noble gas.

- Element \(\mathrm{K}\text{)

\(\mathrm{K}\) is the symbol for Potassium. Potassium is part of Group 1, which is classified as an alkali metal.

- Element \(\mathrm{Cl}\text{)

\(\mathrm{Cl}\) is the symbol for Chlorine. Chlorine belongs to Group 17, classified as a halogen.

Key concepts

alkali metals

Alkali metals are found in Group 1 of the periodic table. They include elements like lithium (Li), sodium (Na), and potassium (K). These metals are highly reactive, especially with water, forming alkaline hydroxides and releasing hydrogen gas. They have one electron in their outermost shell, which makes them eager to lose that electron and form positive ions.
Common characteristics of alkali metals:

• Soft and can be cut with a knife.
• Low melting points compared to most other metals.
• Highly conductive of electricity.

Due to their high reactivity, alkali metals are typically stored in oil to prevent reactions with moisture in the air.

alkaline earth metals

Alkaline earth metals are located in Group 2 of the periodic table. Examples include beryllium (Be), magnesium (Mg), and calcium (Ca). These metals have two electrons in their outermost shell, which they tend to lose to form divalent cations.
Notable properties of alkaline earth metals:

• They are somewhat reactive, though less so than alkali metals.
• They have higher melting points than Group 1 metals.
• They are good conductors of electricity.

These metals form basic (alkaline) oxides and hydroxides and are important in various biological and industrial processes.

transition elements

Transition elements are found in the central block of the periodic table, encompassing Groups 3 to 12. Examples include iron (Fe), copper (Cu), and gold (Au). These metals are characterized by the ability to form variable oxidation states and colored compounds.
Unique traits of transition elements:

• They are generally hard and have high melting and boiling points.
• They often exhibit magnetic properties.
• They can form complex ions with ligands.

Transition elements are widely used in construction, electronics, and as catalysts in various chemical reactions due to their versatile properties.

halogens

Halogens occupy Group 17 of the periodic table. This group includes fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). Halogens have seven electrons in their outermost shell, making them very reactive as they seek to gain one electron to achieve a stable octet.
Key features of halogens:

• They exist in different states of matter: gases, liquids, and solids.
• They form salts when reacting with metals.
• They have high electronegativities and ionization energies.

Halogens are used in everyday products like disinfectants, bleaches, and in the production of plastics and pharmaceuticals.

noble gases

Noble gases are found in Group 18 of the periodic table. This group includes helium (He), neon (Ne), argon (Ar), and xenon (Xe). Noble gases are inert due to their full valence electron shell, which makes them very stable and non-reactive under standard conditions.
Characteristics of noble gases:

• They are colorless, odorless, and tasteless gases.
• They exhibit very low chemical reactivity.
• They have low boiling and melting points.

Due to their stability, noble gases are used in applications like lighting (neon signs), welding, and preserving reactive substances. Helium is notably used in balloons and as a coolant for superconducting magnets.