What is chemistry the study of?

• How plants grow and make food.

• How planets move in space.

• How tiny particles combine to make everything.

• How animals behave in their habitats.

In science, what does the word "theory" mean?

• A wild guess about something.

• An idea that has not been tested.

• A well-tested set of ideas that explains many observations.

• A personal opinion about how things work.

Which famous scientist helped prove that atoms and molecules exist?

• Robert Brown

• Albert Einstein

• Isaac Newton

• Marie Curie

What part of an atom decides what kind of element it is?

• The number of electrons.

• The number of neutrons.

• The number of protons.

• The size of the nucleus.

What is the chemical symbol for the element silver?

• Ag

• Si

• Sv

• Ar

What part of an atom decides what kind of element it is?

• The number of electrons

• The number of neutrons

• The number of protons

• The overall charge

Why are neutrons important in the nucleus of an atom?

• They give the atom its color

• They help electrons move faster

• They stop protons from pushing each other apart

• They make the atom heavier

What do we call atoms of the same element that have a different number of neutrons?

• Ions

• Molecules

• Isotopes

• Compounds