Atoms, Molecules and Elements Unit 4 October-19th-2010

Set up your page in this format: Words Notes Raptors A dangerous and scary dinosaur which should never be underestimated. Cells The basic unit of living things.

Matter Matter is anything that has a mass and takes up space. The Particle Theory of Matter states: 1. Matter is made up of tiny particles (Atoms & Molecules) 2. Particles of Matter are in constant motion. 3. Particles of Matter are held together by very strong electric forces 4. There are empty spaces between the particles of matter. 5. All particles of ONE substance are identical. 6. Temperature affects the speed of the particles. 

What is an Atom? Atoms : the basic particle from which elements are made.

Structure of an Atom Structure Atoms are made up of very small particles called protons neutrons, and electrons.

Nucleus very CENTER of the atom Nucleus very CENTER of the atom. Has the protons and neutrons inside of it. Protons Have a POSTIVE electric charge (+) Neutrons Have NO charge Electrons: Move around the nucleus, and have a NEGATIVE charge.

Organizing Atoms Different atoms have a different number of electrons moving around the nucleus. Electrons that are CLOSE to the nucleus have a LOW ENERGY. Electrons that are FAR AWAY from the nucleus have a HIGH energy. Why is this?

Which electrons have the MOST energy?

2000 electrons = 1 proton. 1 proton = 1 neutron. How much do they weigh? When you look at an atom diagram, it can appear as if there are thousands of electrons all orbiting around the nucleus. They do not account for much of the weight of the atom. 2000 electrons = 1 proton. 1 proton = 1 neutron.

Modeling Atoms Atoms are VERY SMALL and hard to study! ONE sheet of paper is about a million atoms thick! Scientists use MODELS to show what different atoms look like. The most common is the: BOHR Model! (created by Niels Bohr in 1913)

The Bohr Model Shows electrons moving in specific layers (shells) around the center nucleus. The FIRST ORBIT: Has 2 electrons ONLY SECOND ORBIT Has a MAX of 8 electrons.

Third and up orbits: MAX EIGHT ELECTRONS! EXAMPLE: An Atom has 9 electrons circulating the nucleus. How many protons does it have? Draw a picture of this atom.

Which electrons have the MOST energy?

Example 2: An atom has 8 protons, draw a diagram Example 2: An atom has 8 protons, draw a diagram. Example 3: An atom has 16 protons, draw a diagram.

The Periodic Table of The Elements Come on Come on and Meet the Elements! It is time my grade 8’s to meet the elements! We have briefly looked at the Periodic Table of Elements.

Remember how we were talking about the atomic number Remember how we were talking about the atomic number? What is the atomic number? What is the atomic number of the following: Na (Sodium) H (Hydrogen) K (Potassium) Ag (Silver) Cu (Copper)

What does the atomic number tell us What does the atomic number tell us? The atomic number tells us how many protons are in the atoms nucleus! Therefore, it tells us how many electrons there are in the outer orbit!

Therefore, we can calculate the number of neutrons how? Atomic Mass Sometimes, the number of protons DOES NOT equal the number of neutrons in the nucleus. We need to CALCULATE this. Atomic Mass = Protons + Neutrons. Therefore, we can calculate the number of neutrons how?

Examples: Calculate the number of neutrons for the following elements (use your periodic tables). To be completed on the WORKSHEET!!!