Transcript Unit 2: Atomic Structure

Unit 2:
Atomic Structure
The Nucleus
• Small
• Dense (a lot of matter in a small volume)
• Central region of the atom (the rest of the
atom is MOSTLY empty space)
Subatomic Particles
Table O
Proton
Neutron
Electron
Charge
Location
positive
neutral
negative
In nucleus
In nucleus
Size
1 amu
(atomic mass
unit)
Atomic # = #
protons
(known as
nuclear
charge)
1 amu
Outside
nucleus
1/1836 the
mass of a
proton
Info
Mass # =
atomic #
(protons) + #
of neutrons
When an
atom is
neutral,
# protons =
#electrons
Subatomic Particles
•
•
Protons and Neutrons are also called nucleons
Protons + neutrons = mass # (rounded atomic
mass)
1. Example: carbon has an atomic mass of 12.0111, so the
mass # is 12 (round to tenths if possible)
2. Protons and neutrons make up most of the mass of the
atom
•
Periodic Table
1. There is a key at the top of the table
2. The first oxidation # for each element is referred to as the
preferred charge
•
Always assume an atom is neutral unless told
otherwise