Atoms and Atomic Theory Essential Questions: How and why has the Atomic Theory changed over time? How can we describe the molecular motion of the states of matter?

Objectives Students will explain that atoms are the smallest unit of an element and are composed of subatomic particles. Students will analyze models of the scientific theory of atoms. Students will analyze models and describe the motion of particles in solids, liquids, and/or gasses.

Atoms Matter is anything that takes up space and has mass. All matter is made of atoms. Atoms are the basic building blocks of matter. They make up everything around us; Your desk, the board, your body, everything is made of atoms! Atoms are too small to see without powerful microscopes.

Atomic Structure There are two basic components in every atom: Electron Cloud Nucleus

Subatomic Particles Three subatomic particles make up every atom: Charge Location Proton Positive (+) Nucleus or “Core” Neutron No Charge (0) Electron Negative (-) Electron Cloud

Subatomic Particles Electron Cloud: Electrons orbit the nucleus. Nucleus or “Core”: Protons and Neutrons are found in the nucleus.

Atomic Theory Changes over time…

Atomic Theory Because we can not see atoms, we use models to teach and learn about atoms. The atomic theory has changed over time as new technologies have become available. Remember: Scientific knowledge builds on past research and experimentation.

Atomic Theory Timeline Scientist Information Model John Dalton All matter is made of atoms. Atoms are too small to see, indivisible and indestructible. All atoms of a given element are identical.

Atomic Theory Timeline Scientist Information Model J.J Thompson Discovered the negative electron, and predicted that there also must be a positive particle to hold the electrons in place.

Atomic Theory Timeline Scientist Information Model Ernest Rutherford Discovered the nucleus of an atom and named the positive particles in the nucleus “protons”. Concluded that electrons are scattered in empty space around the nucleus.

Atomic Theory Timeline Scientist Information Model James Chadwick Discovered that neutrons were also located in the nucleus of an atoms and that they contain no charge. Neutrons

Atomic Theory Timeline Scientist Information Model Neils Bohr Concluded that electrons are located in planet-like orbits around the nucleus in certain energy levels.

Scientist Information Model (Many Scientists!) The Modern Atomic Theory Electrons do not orbit the nucleus in neat planet-like orbits but move at high speeds in an electron cloud around the nucleus.

Think-Pair-Share! Take a minute to read the essential question as I read it aloud: “How and why has the Atomic Theory changed over time?” After you have jotted down your notes in the space on your guided notes, exchange your thoughts with your partner. We will have share-outs and discuss the answer.

http://www.brainpop.com/science/matterandchemistry/atomicmodel/ Additional video resource: http://studyjams.scholastic.com/studyjams/jams/science/matter/solids-liquids-gases.htm

Atoms and Atomic Theory Essential Questions: How and why has the Atomic Theory changed over time? How can we describe the molecular motion of the states of matter?

solid liquid gas Three states of matter At room temperature most substances exist in one of three physical states. solid liquid gas

Solids The particles in a solid are very tightly packed and vibrate in place. Solids have a definite volume and shape.

Particles in a solid – animation

Liquids The particles in a liquid are close together but can move and flow past one another. Liquids have a definite volume but they do not have a definite shape. This is why liquids like water take the shape of the container they are in. Picture was taken at the exact moment these water balloons were popped!

Particles in a liquid – animation

Gases Particles in a gas have higher amounts of energy than those in a solid or liquid. Gases do not have a definite shape or volume. When placed in a container, it fills up the entire container and spreads out as far as possible.

Particles in a gas – animation

Molecular Motion Adding heat Removing heat

In your groups, you will rotate clockwise after 4 minutes through the 5 stations. You will write all information on the Gallery Walk handout. Stay with your group at all times. Do not move ahead or go back, wait for the timer to move. You may discuss possible answers with your group members. Raise your hand if you need assistance after you have asked your group members.

Independent Practice