Prior Knowledge Check: Atoms & Chemical Properties

All matter is made up of tiny particles called ___________ that are too small to be seen. They are the smallest particles that can still be considered a(n) ___________.

• molecules, element

• atoms, molecule

• atoms, element

• molecules, compound

• cells, element

Answer explanation

Atoms are considered the building blocks of all matter, while cells are the building blocks of living things. All cells are made of billions of tiny atoms!

An element is made up of only one type of atom - elements/atoms cannot be chemically interconverted or broken down into simpler substances.

Atoms contain positive, negative, and neutral particles. What happens when two positively charged particles are close together?

• they repel each other

• they cancel each other out

• they attract each other

• they have no effect on each other

Answer explanation

like charges repel, while opposite charges attract

Scientists observe patterns in matter. They organize matter into groups based on shared physical and chemical properties. Which statement describes a chemical property that many elements might share?

• bonds easily with oxygen in the air

• boils between 90°C and 100°C

• shines when polished

• floats in water

Answer explanation

A physical property is a characteristic of a substance that can be observed or measured without changing the identity of the substance. Physical properties include color, density, hardness, and melting and boiling points. A chemical property describes the ability of a substance to undergo a specific chemical change.

Words made from letters of the alphabet are similar to molecules made from atoms. Based on what you already know about matter, which statement best explains this comparison?

• Atoms can make many different molecules, just like letters can make many different words.

• Molecules must contain many different atoms, just like words must contain many different letters.

• There are 26 different atoms that are used to form molecules, just like there are 26 different letters that are used to form words.

• There are no rules for how letters combine to make words, just like there are no rules for how atoms combine to make molecules.

Acids are a group of molecules with similar physical and chemical properties. Acids react with metal, but vegetable oil does not. What can you infer from this observation? Choose the two statements that apply.

• Acids and oil have different properties because they have different shapes.

• Vegetable oil is most likely some type of acid.

• The atoms present in molecules affect their properties.

• The combination of atoms in acids and oil result in very different properties.

In the space below, draw your best idea of what an atom looks like. Include subatomic particles, including their electric charge and location

Answer explanation

Atoms are made of tiny, "subatomic" particles:

- protons (positive charge)

- neutrons (neutral charge)

- electrons (negative charge)

Protons and neutrons hang out together at the center of an atom and form the "nucleus". Electrons orbit the nucleus in specific paths.

What does an element's "Atomic Number" tell you?

• the number of protons in the nucleus

• the number of protons + neutrons in the nucleus

• the number of electrons orbiting the nucleus

• the number of protons + electrons in one atom

Which subatomic particle has the SMALLEST mass?

• protons

• neutrons

• electrons

Answer explanation

Did you know that it takes almost 1,840 electrons to equal the mass of just ONE proton or neutron?