Elements, Compounds, and Mixtures - Multiple Choice Questions

What is the fundamental building block of matter?

• Molecule

• Atom

• Compound

• Mixture

Which of the following best describes an element?

• A substance composed of two or more different atoms

• A substance that cannot be broken down into simpler substances

• A mixture of different substances

• A chemical compound

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

• Molecule

• Proton

• Atom

• Electron

Which of these is an example of a compound?

• Oxygen (O₂)

• Gold (Au)

• Water (H₂O)

• Carbon (C)

What is a mixture?

• A) A chemically combined substance

• B) A substance with a fixed composition

• C) A combination of two or more substances that are not chemically combined

• D) A pure chemical substance

What is the charge of a proton?

• Neutral

• Positive

• Negative

• None of the above

What subatomic particles are found in the nucleus?

• Protons and neutrons

• Electrons and protons

• Neutrons and electrons

• Only neutrons

What is the charge of an electron?

• Positive

• Neutral

• Negative

• No charge

How many electrons does an oxygen atom have?

• 6

• 8

• 10

• 12

What determines an element’s identity?

• The number of protons in the nucleus

• The number of neutrons in the nucleus

• The number of electrons in the outer shell

• The atomic mass of the element