Which of the following elements is classified as a nonmetal?

• A. Sodium (Na)
• B. Oxygen (O)
• C. Calcium (Ca)
• D. Iron (Fe)

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the classification of elements on the periodic table. Elements are broadly categorized into metals, nonmetals, and metalloids based on their physical and chemical properties.
2. Step 2: Recall that metals are typically good conductors of heat and electricity, malleable, ductile, and have a shiny appearance. Nonmetals, on the other hand, are poor conductors, often brittle in solid form, and lack metallic luster.
3. Step 3: Identify the given elements: Sodium (Na), Calcium (Ca), and Iron (Fe) are all metals. Sodium and Calcium are alkali and alkaline earth metals respectively, while Iron is a transition metal.
4. Step 4: Recognize that Oxygen (O) is a nonmetal. It is a gas at room temperature, a poor conductor of electricity, and essential for combustion and respiration processes.
5. Step 5: Conclude that among the options, Oxygen (O) is the element classified as a nonmetal.