Atomic Structure, Isotopes,
and Mass #
Pages 26 and 27 in INB. Set up 27 for Cornell Notes
Chapter 5
Learning outcomes
• Describe the structure of the atom.
• On page 26- Quick Write- What do you know
about the structure of the atom?
I. The Structure of the Atom
A. Three particles make up the
structure of atoms:
1) protons …. positive charge (+)
2) neutrons … no charge (neutral)
3) electrons …negative charge (-)
B. These particles are located in one of
two locations:
1) in the nucleus – protons and neutrons
2) around the nucleus - electrons
Learning outcomes
Explain modern atomic theory and its
development.
• Page 26 in INB Quick Write- what do you
think this refers to? What do you know
already about atomic theory. Think about
Greeks, Dalton, Thomson, Rutherford, Bohr,
and Quantum mechanics.
EQ
What information is represented by the mass
number and atomic number of an atom?
Learning Outcomes
• Use the periodic table to identify atomic #
• Use nuclide name and/symbol to identify
subatomic particles.
C. The mass of an atom is concentrated in
the nucleus …
mass #= sum of protons + neutrons
D. The Periodic Table indicates the
number of protons in each element:
Atomic number = number of protons
* The atomic number identifies the
element
E. Shorthand notation is used to indicate
the element, atomic number and atomic
mass:
At . Mass
At .#
1
1
H
Symbol
12
6
C
23
11
Na
Hydrogen
1 proton
0 neutrons
Carbon
6 protons
6 neutrons
Sodium
11 proton
12 neutrons
Hydrogen-1
Carbon-12
Sodium-23
On page 26- Practice: Indicate the name,
number of protons and number of
neutrons
80
201
17
35
80
8
O
56
?
Fe
Br
64
29
?
Hg
79
35
?
II. Isotopes
A. “Atoms of the same element
that have different atomic
masses because they have
different numbers of neutrons”
B. The atomic number identifies the
element…
C. The atomic mass = sum of protons +
neutrons
D. Only neutrons can change the atomic
mass
Examples:
20
10
Ne
Neon
10 proton
10 neutrons
21
10
Ne
Neon
10 proton
11 neutrons
22
10
Ne
Neon
10 proton
12 neutrons
III. Electrons
A. A NEUTRAL atom has the same
number of electrons as protons
Review- Quiz Wednesday 10/2
• Classify elements as metals, nonmetals, or
metalloids according to their properties and
placement on the Periodic Table.
• Identify the Periodic Table location and
properties of alkali metals, alkaline earth
metals, halogens, noble gases, and transition
metals.
• Understand the trends present in the modern
Periodic Table.
IV. The Periodic Table
A. The periodic table is arranged in
specific rows and columns according
to their chemical behavior
B. Specific regions have been
named:
Representative
Group
Period
Noble
Metals
Gases
Non
metals