Atomic Structure and the Periodic Table

1. Atomic Structure and the Periodic Table Chapter 10 Notes

2. Chemical Symbols Chemical symbol – an abbreviated way to write the name of an element. -example: Carbon – C Proton – positively charged particle found in the nucleus of an atom. Neutron – neutrally charged particle found in the nucleus of an atom. Atomic number – the number of protons in the nucleus of an atom.

3. The Electron Cloud • Electron cloud – cloud that surrounds the nucleus of an atom that describes the region in which an electron is most likely to be. • Example: students in a school

4. Energy Levels • You can represent the energy differences of the electrons by picturing the atom as having different energy levels. • Example: shelves of a refrigerator door (table 10-3)

5. Masses of Atoms • Mass number = the sum of the number of protons and the number of neutrons in the nucleus of an atom. • Number of neutrons = mass number – number of protons.

6. Isotopes • Atoms of the same element that have different numbers of neutrons. • See table 10-4 on pg. 279

7. Average atomic mass • Average atomic mass = the average mass of the mixture of an element’s isotopes. • Example: boron-11

8. In-class Assignment • Do pg. 281, 1-3