Atoms and
Elements
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The Atom
Atomic Number
Mass Number
Isotopes
Elements
Periodic Table
What do all of these things
have in common?
What Are Atoms?
• Atoms are the building blocks of
matter.
• So what is “matter”?
• Anything that has mass AND takes
up space.
Which of the following are
considered matter
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Pizza
Wood
Love
Soil
Heat
Hope
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Air
Silk
Beauty
Juice
X- Rays
Sunshine
Subatomic Particles:
Smaller Parts of an Atom
Particle Symbol
Charge
Electron
e-
-1
Proton
p+
+1
Neutron
n
0
Location of Subatomic
Particles
10-13 cm
electrons
nucleus
protons
neutrons
10-8 cm
Number of Electrons
An atom is neutral = zero net charge
because the # of protons = # of
electrons
Atomic Mass = # of p+ + # of n
Atomic Number = # of protons = # of
electrons
An atom with a charge is
called an ion (unequal #’s
of protons and electrons).
Electron Levels
(Shells)
 Contain electrons that are similar in
energy and distance from nucleus
 Low energy electrons are closest to the
nucleus
 Identify by letters k, l, m, n, o, p, q
 The first shell (k) is lowest in energy, 2nd
level next and so on k<l<m<n<o<p<q
Order of Electron Filling
The smallest shell must be filled before the
next size can contain any electrons.
K-Shell
L-Shell
M-Shell
2 electrons
8 electrons
8 electrons
Order of filling for the first 16 electrons
Shell
k
2e
l
8e
m
6e
Atomic Number
Counts the number
of
?
in an atom
Atomic Mass
Counts the number
of
?+?
in an atom
Subatomic Particles in
Some Atoms
Which number do you think is the atomic number? How do you know?
16
O
31
P
65
8
15
30
8 p+
8n
8 e-
15 p+
16 n
15 e-
Zn
30 p+
35 n
30 e-
What Are Isotopes?
 Atoms with the same number of protons,
but different numbers of neutrons.
 Atoms of the same element (same
atomic number) with different atomic
masses.
Isotopes of Chlorine
35Cl
17
chlorine - 35
37Cl
17
chlorine - 37
Learning Check
Naturally occurring carbon consists of
three isotopes, C-12, C-13, and C-14.
State the number of protons, neutrons,
and electrons in each of these carbon
atoms.
12C
6
13C
6
14C
6
#p
_______
_______
_______
#n
_______
_______
_______
#e
_______
_______
_______
What Are Elements?
 Pure substances made up of all the
same type of atom (same # of: p+, n, e-)
 The 4 most abundant elements on Earth
are carbon, oxygen, hydrogen, and
nitrogen (POINTER: COHN or NOCH)
 112 elements known today
Examples:
carbon
gold
calcium
What element do these
things have in common?
Here’s a Hint…
IRON (Fe) Latin:
ferrum
• Cheapest…
• Most common…
• Most useful…
• Used extensively for the making
of STEEL
IRON (Fe) Latin:
ferrum
It also carries
oxygen in
hemoglobin in
red blood cells.
Symbols of Elements
 Use 1 or 2 letter abbreviations
 Capitalize the first letter only
Examples:
C carbon
N nitrogen
F fluorine
O oxygen
Co cobalt
Ca calcium
Br bromine
Mg magnesium
Symbols from Latin Names
Element
Copper
Gold
Lead
Mercury
Potassium
Silver
Sodium
Tin
Symbol
Cu
Au
Pb
Hg
K
Ag
Na
Sn
Latin name
cuprum
aurum
plumbum
hydrargyrum
kalium
argentum
natrium
stannum
% Major Elements
in the Body
O 65.0 %
C 18.0
H 10.0
N 3.0
Ca 1.4
P 1.0
Mg 0.50
K
S
Na
Cl
Fe
Zn
0.34
0.26
0.14
0.14
0.004
0.003
Take a guess what the
correct symbol is for the
element!
Select the correct symbol for each:
A. Calcium
1) C
2) Ca
3) CA
B. Sulfur
1) S
2) Sl
3) Su
C. Iron
1) Ir
2) FE
3) Fe
Take a guess what the
correct element is!
Select the correct name for each:
A. N
1) neon
2) nitrogen 3) nickel
B. P
1) potassium
2) phogiston
3) phosphorus
C. Ag
1) silver 2) agean
3) gold
Atomic Theory
 Atoms are the building
blocks of all matter, which
included elements
 Similar atoms in each
element
 Different from atoms of
other elements
Periodic Table
The periodic table is an
arrangement of the elements
according to:
•The number of protons,
neutrons, and electrons
•The way they look
•The way they act
The Periodic Table
 Shows the mass number and atomic
number
 Gives the symbol of the element
mass number
23
atomic number
Na
11
Groups of Elements
 Vertical (up and down) columns on
the periodic table
 Indicates the number of electrons
on the outer most shell called
valence electrons.
Periods on the Periodic
Table
 Horizontal (left to right) rows on the Periodic
Table.
 Numbered 1-7
 Indicates the number of
orbitals or shells the element
has.
Periods on the Periodic
Table
1
2
3
4
5
6
Using The Periodic
Table
• In your notes, use your periodic tables to
determine the following for the elements at
the bottom.
• The number of protons
• The number of neutrons
• The number of shells
• The number of electrons on the outer
most shell (valence electrons)
• Draw the atoms for each
Calcium (Ca), Magnesium (Mg),
Chlorine (Cl)