1. What are isotopes? Section 14-5

2. Isotopes Atomic numbers never change, but atomic masses can change. In this case, there will be a different number of neutrons. Atoms of the same element that have different atomic masses are called isotopes.

3. Isotopes of common elements

4. How are electrons arranged in an atom? Section 14-6

5. Energy Levels Electron’s position around the nucleus cannot be predicted. So the electrons are said to be in an “electron cloud”. Compared to bees buzzing around a beehive. Electrons are arranged in energy levels. Each level is a different distance away from the nucleus. The lowest energy is nearest the nucleus. Energy increases as electrons go away from the nucleus.

6. Energy Levels The first level can have 2 electrons. The second level can have 8 electrons. The third level can have 18 electrons. Each level afterwards can have up to 32 electrons each. Electrons fill the first energy level then the second energy level and so on. If electron gains enough energy, it jumps to higher level, and visa versa

7. H.W. p. 267 check/apply 1-8 Wkst. 14-5 Enrichment 14-5 p. 269 check/apply 1-8 wkst. 14-6