1. Element Review Atoms are made of 3 main parts: Protons (positive) Neutrons (no charge) Electrons (negative) The protons and neutrons are located in: The nucleus The electrons are located in: The electron cloud

2. Element Review The “Atomic Number” corresponds to the number of: Protons The number of protons determine which element the atom is. Most of the weight comes from which parts of the atom: The protons and the neutrons The “Atomic Weight” is a combination of the protons plus the neutrons.

3. The Periodic Table A way of organizing the elements. Atomic Number Element Symbol Element Name Atomic Weight

4. Practice Identifying Elements If I know I have 20 protons and 20 neutrons, which element do I have? Atomic Number = # of protons Atomic Number = 20 Element is Calcium (Ca) What is the Atomic Weight of Calcium? Atomic Weight = # of protons + # of neutrons 20 + 20 = 40 Calcium has an Atomic Weight of 40 How many electrons does Calcium have? # of electrons = # of protons in neutral element Calcium has 20 electrons

5. Hands-on Exercise In teams of 2, create your element. Pink Marshmallows: Protons White Marshmallows: Neutrons Cotton: Electron Cloud Fill out the answer sheet and create a Periodic Table Tile. When you are finished: Place your paper on your desk with your element. I will come check your answer. Get another unknown element baggie or begin working on your homework.

6. Wrap-up 3 parts of the atom: Protons (positive) Neutrons (no charge) Electrons (negative) The number of protons determines which element you have. Remember: These models are NOT to scale! If the nucleus was the size of a pin head, how big do you think the entire atom would be? The size of the Astrodome! In other words: Atoms are mostly empty space.

7. Thought Question of the Day If we are made up of millions of atoms and atoms are mostly empty space, why are we solid?