Question

Identify each of the following elements as a metal, nonmetal, or metalloid: (a) gallium, (b) molybdenum, (c) tellurium, (d) arsenic, (e) xenon, (f) cadmium.

Short answer

(a) Gallium - Metal, (b) Molybdenum - Metal, (c) Tellurium - Metalloid, (d) Arsenic - Metalloid, (e) Xenon - Nonmetal, (f) Cadmium - Metal.

Step-by-step solution

Classify Gallium (Ga)

Gallium is found in Group 13 (Column 13) and Period 4 (Row 4) in the periodic table. It is on the left side and below boron (B). Therefore, gallium is classified as a metal.

Classify Molybdenum (Mo)

Molybdenum is found in Group 6 (Column 6) and Period 5 (Row 5) in the periodic table. It is located on the left side of the periodic table. Hence, molybdenum is classified as a metal.

Classify Tellurium (Te)

Tellurium is found in Group 16 (Column 16) and Period 5 (Row 5) in the periodic table. It lies on the staircase-like boundary between metals and nonmetals. Consequently, tellurium is classified as a metalloid.

Classify Arsenic (As)

Arsenic is located in Group 15 (Column 15) and Period 4 (Row 4) in the periodic table. It is also located along the staircase-like boundary separating metals and nonmetals. As a result, arsenic is classified as a metalloid.

Classify Xenon (Xe)

Xenon can be found in Group 18 (Column 18) and Period 5 (Row 5) in the periodic table. It is located on the right side, within the group of noble gases. Thus, xenon is classified as a nonmetal.

Classify Cadmium (Cd)

Cadmium is situated in Group 12 (Column 12) and Period 5 (Row 5) in the periodic table. It is placed on the left side of the periodic table. Therefore, cadmium is classified as a metal. In summary: (a) Gallium - Metal (b) Molybdenum - Metal (c) Tellurium - Metalloid (d) Arsenic - Metalloid (e) Xenon - Nonmetal (f) Cadmium - Metal

Key concepts

Metals

Metal elements are typically found on the left side of the periodic table. They are known for their shiny appearance and high conductivity of electricity and heat. Metals are usually malleable, allowing them to be shaped or molded without breaking. They also tend to have high melting and boiling points.
Here are some key features of metals:

• They lose electrons easily, forming positive ions.
• They are typically solid at room temperature (except for mercury).
• Common examples include iron, gold, silver, and aluminum.

In our exercise, gallium, molybdenum, and cadmium are classified as metals because of their positioning on the periodic table and their physical characteristics.

Nonmetals

Nonmetals are found on the right side of the periodic table. They differ greatly from metals. These elements are more diverse in their properties, lacking the shininess and malleability of metals. Nonmetals can be gaseous, liquid, or solid at room temperature.
Some key characteristics include:

• They tend to gain electrons in reactions, forming negative ions.
• Nonmetals are poor conductors of heat and electricity.
• Examples include oxygen, nitrogen, and sulphur.

Xenon, in our exercise, is classified as a nonmetal due to its position in the noble gas group on the right side of the periodic table.

Metalloids

Metalloids possess properties in between those of metals and nonmetals. They are found along the staircase-like line that divides metals and nonmetals on the periodic table. This gives them unique traits that make them suitable for various applications.
Key characteristics:

• Metalloids may conduct electricity but not as well as metals.
• They are often semi-conductors, making them valuable in the electronics industry.
• Examples include silicon, boron, and germanium.

In our exercise, tellurium and arsenic are classified as metalloids due to their boundary positions and intermediate properties.

Chemical Elements

Chemical elements are the most basic forms of matter, consisting of atoms with the same number of protons. The periodic table organizes these elements based on their atomic number, electron configurations, and recurring chemical properties.
A few important points about chemical elements:

• They cannot be broken down into simpler substances by chemical means.
• Each element is identified by a unique symbol, often derived from its English or Latin name.
• There are currently 118 recognized elements.

Understanding chemical elements and their properties is crucial for identifying whether elements like those in our exercise should be classified as metals, nonmetals, or metalloids.

Group and Period Classification

The periodic table is organized into groups (columns) and periods (rows) that help us understand the properties of each element. Group classification reveals the number of valence electrons present in an element, while periods reflect the number of electron shells.
Key aspects include:

• Elements in the same group often share similar chemical properties.
• The properties of the elements change in a predictable way across a period.
• This arrangement helps predict how an element will react chemically.

In our exercise, the group and period placement helped determine the classification of each element, such as placing gallium and cadmium in the metal category based on their group and period.