Download Chapter 3 Chemical Foundations

Chapter 3 Chemical Foundations
The Elements: The name for the elements come from many sources. Often the elements
names are derived from Greek, Latin, or German words that describe a property of the
element.
NOTE:
Ex. Gold (Au) come from aurum- a Latin word meaning “shinning dawn.”
Element symbols are used to represent the elements. They usually (not always) contain
the first or first two letters of the element name.
Ex. Fluorine
F
Zinc
Zn
See textbook pg 51 for more information about common symbols.
Subatomic Particles
Particle
Symbol
Proton
Neutron
Electron
p+
n
e-
Mass (g)
1.67262x10-24
1.67262x10-24
9.10939x10-28
Charge
(Coulomb)
+1.6022x10-19
0
-1.6022x10-19
Relative
Charge
+1
0
-1
Location in
Atom
Inside Nucleus
Inside Nucleus
Outside Nucleus
Atomic Number, Mass Number, and Nucleus
atomic number (Z) =
mass number (A) =
element symbol (X) =
Note: mass number=
Therefore …. mass number =
……. A= Z + number of neutrons ….. Number of neutrons = A-Z
Note: For any given element on the periodic table:
Number of protons =
In order to symbolically represent elements and isotopes chemists use the following
notation:
Mass Number
X
Atomic number
Ex:
Isotopes are atoms with identical atomic numbers but different mass numbers (that is,
same number of protons but different number of neutrons)
Exercise:
1. How many protons, electrons, and neutrons are in an atom of 197Au ?
2. Magnesium has three isotopes, with mass numbers of 24, 25, 26.
a. Write the complete chemical symbol for each of them.
b. How many neutrons are in an atom of each isotope?
3. Fill in the gaps in the following table, assuming each column represents a neutral
atom.
65
Zn
Symbol
Protons
44
92
Neutrons
57
49
Electrons
38
47
Mass no.
108
235