Which of the following is a pure substance with the smallest unit made up of atoms of two or more elements joined by chemical bonds?

A. Carbon
Incorrect. Carbon is an element.

B. Carbon Dioxide
Correct!

C. Gold
Incorrect. Gold is an element.

D. Chicken noodle soup
Incorrect. Chicken noodle soup is a mixture.

Which of the following describes an element?

• Has particles that are all alike
• Can be broken down into simpler substances
• Has unique sets of properties
• Can join together to form compounds

A. I and II only
Incorrect. An element does have particles that are all alike, but elements cannot be broken down into simpler substances.

B. II and III only
Incorrect. An element does have a unique set of properties, but elements cannot be broken down into simpler substances.

C. I, III and IV only
Correct!

D. I, II, III, and IV
Incorrect. Elements cannot be broken down into simpler substances.

Which of the following is a true statement?

A. Both elements and compounds are represented by chemical symbols.
Incorrect. Elements are represented by chemical symbols and compounds are represented by chemical formulas.

B. Both elements and compounds are represented by chemical formulas.
Incorrect. Elements are represented by chemical symbols and compounds are represents by chemical formulas.

C. Elements are represented by chemical formulas, while compounds are represented by chemical symbols.
Incorrect. Elements are represented by chemical symbols, and compounds are represented by chemical formulas.

D. Elements are represented by chemical symbols while compounds are represents by chemical formulas.
Correct!

A substance is analyzed in a laboratory, and when viewed under an electron microscope, it is revealed that it contains only one kind of atom. Is the substance an element, a compound, or a mixture?

A. Element
Correct!

B. Compound
Incorrect. Compounds are made up of more than one type of atom.

C. Heterogeneous Mixture
Incorrect. Mixtures are made up of more than one type of atom.

D. Homogeneous Mixture
Incorrect. Mixtures are made up of more than one type of atom.