Download Atomic Structure and the Periodic Table

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 103)
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