Chemistry quiz

Which of the following is the smallest unit of matter?

• Atom
• Molecule
• Compound
• Element

Answer explanation

An atom is the smallest unit of matter that still has the properties of an element.

A substance made of only one type of atom is called:

• Compound
• Element
• Molecule
• Mixture

Answer explanation

An element is made of only one kind of atom.

Which of these is a compound?

• O₂
• N₂
• H₂O
• He

Answer explanation

Water is a compound because it is made of hydrogen and oxygen bonded together.

Tags

NGSS.MS-PS1-1

Which of these is a molecule made of the same element?

• CO₂
• H₂O
• NH₃
• O₂

Answer explanation

O₂ is a molecule made of two oxygen atoms, so it is the same element.

Tags

NGSS.MS-PS1-1

The atomic number of an element tells you the number of:

• Protons
• Neutrons
• Electrons
• Energy levels

Answer explanation

The atomic number is the number of protons in an atom.

Tags

NGSS.MS-PS1-5

The atomic mass of an atom is mostly the total of its:

• Electrons
• Protons and neutrons
• Neutrons only
• Protons only

Answer explanation

Most of an atom’s mass comes from the protons and neutrons in the nucleus.

What is the chemical symbol for sodium?

• S
• Sn
• Na
• So

Answer explanation

The symbol for sodium is Na.

Where is the atomic number usually found on an element square in the periodic table?

• At the bottom
• It is not shown
• On the side
• At the top

Answer explanation

On most classroom periodic tables, the atomic number is shown at the top of the element square.

Which state of matter has a definite shape and a definite volume?

• Solid
• Gas
• Liquid
• Water vapor

Answer explanation

A solid keeps its own shape and volume.

Which state of matter takes the shape of its container but keeps the same volume?

• Solid
• Liquid
• Both liquid and gas
• None of these

Answer explanation

A liquid takes the shape of its container, but its volume stays the same.