Cornell Notes 6.4 Electrons in the Atom February 15, 2012 Pages 157 and 159

Quick Review! Atoms are made of 3 subatomic particles: protons, neutrons, and electrons. Neutron Proton Electron

+ + + + + + Quick Review Protons give atoms their identity. 1 Proton - H 2 Protons – He 3 Protons - Li

You’re not going anywhere. Quick Review Neutrons hold protons together in the nucleus. You’re not going anywhere. Settle down. You’re scum! + + I hate you!

Quick Review Electrons give elements their properties like: Color Malleability (Will It Bend when you hit it with a hammer…) Odor Shape

The only real exception is mass. An atom’s mass is determined by number of protons plus number of neutrons!

How electrons make color

Electrons’ Speed Most of the time, electrons go really really fast. So fast that you can’t actually see it or know exactly where it is. The area electrons move in is known as the energy levels or electron clouds

Energy levels Electrons orbit in differing energy levels. You will hear me call these levels “rings” or “shells” 2nd Level Nucleus 3rd Level 1st Level

6.2 Electrons and energy levels In the current model of the atom, we think of the electrons in an atom as moving around the nucleus in an area called an electron cloud. The energy levels occur because electrons in the cloud are at different average distances from the nucleus.

6.2 Electrons and energy levels The first energy level can accept up to two electrons. The second energy levels hold up to eight electrons.

Ground State As you saw earlier, electrons bounce up to higher levels when they absorb energy, and go back down to lower levels when they release it. The “start point” of these electrons (their original low energy levels) is called the ground state

Counting Levels You can tell how many electron rings an element has in the ground stateby counting down from the top of the periodic table. One Ring Two Rings Four Rings Six Rings

Electron Rings 1e- 2e- 3e- 4e- 5e- 6e- 7e- 8e- You can tell how many electrons are in the outermost ring in an element by counting from the left of the periodic table. Li Be B C N O F Ne Na Mg Al Si P S Cl Ar 1e- 2e- 3e- 4e- 5e- 6e- 7e- 8e-

Big Definition Type Word! The electrons on the outer ring are called valence electrons. Even though the outer levels past three have more than eight elements in it, the outermost energy level will never have more than eight electrons. Note that you skip the transitional metals in the middle of the periodic table when you count!