Understanding Atoms and Their Compositions (1)

Which of the following statements best describes the basic principle of atomic theory?

• All matter is made of molecules.

• All matter is made of atoms.

• All matter is made of cells.

• All matter is made of energy.

What is an element?

• A substance made of two or more types of atoms chemically combined.

• A substance made of only one type of atom.

• A mixture of different substances.

• A substance that can be separated by physical means.

Which of the following is a compound?

• Gold (Au)

• Air

How are mixtures different from compounds?

• Mixtures are made of only one type of atom.

• Mixtures can be separated by physical means, while compounds cannot.

• Compounds can be separated by physical means, while mixtures cannot.

• Mixtures have a fixed ratio of atoms.

Which of the following is NOT a mixture?

• Salt water

• Air

• Soil

If a substance is made up of two or more elements chemically combined in a fixed ratio, it is called a:

• Mixture

• Element

• Compound

• Solution

Which diagram best represents a mixture?

• All particles are identical.

• Two types of atoms bonded together in every particle.

• Different types of particles not bonded together.

• Only one type of atom present.

Which of the following is an example of an element?

• Water

• Iron (Fe)

• Salt

• Sugar

What is the smallest unit of an element that retains the properties of that element?

• Molecule

• Atom

• Compound

• Mixture

Which of the following substances can be separated into simpler substances by chemical means but not by physical means?

• Mixture

• Element

• Compound

• Solution