Download Atoms

Anatomy
of an
Atom
Nucleus – The central part of an atom
made up of Protons and Neutrons.
Neutron – Particle found in the
nucleus which has No Electrical
Charge, and a mass about the same
size as a Proton.
Proton – Particle in the nucleus,
which has a Positive Electrical
Charge.
Electron – Particle that orbits the
nucleus of an atom and has a
Negative Electrical Charge. They
move more rapidly around the
outer areas of the atom. Their
arrangement determines the
chemical properties of an atom.
Atoms are made up of pieces
particle
symbol
“relative”
mass
“relative”
charge
location
proton
p+
1
+1
nuclear
neutron
no
1
0
nuclear
electron
e-
negligible
-1
extra nuclear
“relative” vs. “absolute”
particle
“relative”
mass
“absolute”
mass
“relative”
charge
“absolute”
charge
p+
1
1.67 x 10-24 g
+1
+1.60 x 10-19 C
no
1
1.67 x 10-24 g
0
0
e-
negligible
9.09 x 10-28 g
-1
-1.60 x 10-19 C
various atoms are arranged on
The Periodic Table
Over 100 various kinds of building blocks exist
Looking at an example we find all sorts of information.
6
C
Atomic Number
Symbol
Carbon
Atomic Mass
12.0111
Atomic number
(a.k.a. proton number)
•Indicates the # of p+’s an atom has
•Identification Tag of the element
example: each and every C atom has 6 p+’s
5 p+’s would make it B
7 p+’s would make it N
Symbol
•The abbreviated shorthand used to represent a
particular atom
Rules
Atoms are represented by a 1, 2, or in some cases 3
letter Arabic letter code.
The 1st letter is always capitalized; the others (if there
are any) are always expressed in the lower case.
Be careful using symbols
Po  PO
Atomic Mass
• Indicates the amount of matter present in an
atom
Mass = ( # p+) + ( # no) + (# e-)
But considering the negligible mass of the electron
Mass = ( #
+
p)
+(#
o
n)
Looking back at the original example:
6
C
Carbon
12.0111
#
charge
p+
6
+6
no
6
0
e-
6
-6
18
0
Example #2
#
charge
p+
47
+ 47
no
61
0
e-
47
- 47
155
0
47
Ag
Silver
107.8682
Review problem #1
Fill in the chart below
#
92
U
Uranium
238.0289
p+
no
e-
charge
Review problem #2
How many protons are in the following atom?
10
Ne
Neon
20.1797
Review problem #3
How many neutrons are in the following atom?
11
Na
Sodium
22.98977
Review problem #4
How many electrons are in the following “neutral”
atom?
3
Li
Lithium
6.941