Atomic Structure and the Periodic Table Chapter 10 Notes

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.

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

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)

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.

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

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

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