S

Chemistry Lesson 2What is an Atom?

Do-Now

What is the definition of an element?

Atoms

Think about the word “Atom”

What do you already know about the Atom? List it on the back of your “do-now” worksheet

Atoms

Now that you’ve listed some things you know about atoms, turn to the person next to you and share.

What is an Atom?

An Atom is the basic particle from which all elements are made.

Atoms are made up of smaller particles called protons, electrons, and neutrons

What is an Atom?

A proton has a positive charge (+)

A electron has a negative charge (-)

A neutron has neither a positive or negative charge. It is neutral.

What is an Atom?

In an atom, the number of protons is the same as the number of electrons.

The electrical charges balance, so the atom as a whole is neutral

Parts of an Atom

Parts of an Atom

The two main parts of an atom are the nucleus and the electron cloud.

The nucleus is the very small center core of the atom. It contains protons and neutrons.

The electron cloud is a cloud of negative charge that surrounds the nucleus. It contains electrons.