Download Chapter 3 Chemical Foundations

Chapter 4 Atomic Structure
THE HISTORY:
Refer to your inspiration app time line to study!
Exercise: Relate the main atomic theory models to the following treats!
Gobstopper
Tootsie pop
Chocolate chip cookie
Jellybean
THE ATOM:
An atom is the smallest particle of an element that retains its ______________________.
How small is an atom?
What is the structure of an atom?
Subatomic Particles
Particle
Symbol
Proton
Neutron
Electron
p+
n
e-
Mass (g)
1.67x10-24
1.67x10-24
9.11x10-28
Relative Mass Relative
(mass of
Charge
proton =1)
1
+1
1
0
1/1840
-1
Location in
Atom
Inside Nucleus
Inside Nucleus
Outside Nucleus
THE ELEMENTS:
What makes elements different from one another?
atomic number (Z) =
mass number (A) =
element symbol (X) =
Note: mass number=
Therefore …. Number of neutrons =
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:
Oxygen
Isotopes are atoms with identical atomic numbers but different mass numbers (that is,
same number of protons but different number of neutrons) Note: they also have different
mass numbers.
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
Neutrons
57
Electrons
Mass no.
92
49
38
47
108
238