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Name ___________________________________ Date ___________________Period _________
Atomic Structure
What is an atom? _________________________________________________________________
Democritus ____________________________________________________
Dalton’s Atomic Theory
1. __________________________________________________________
2.___________________________________________________________
3. ___________________________________________________________
4. ___________________________________________________________
Discovery of the Electron by _________________________ by using a cathode ray tube.
____________ discovered the __________ and __________ of an electron
Discovery of the Nucleus by _________________________. Concluded __________________
________________________________________________________
Bohr
_____________________________________________________________
The atom contains three subatomic particles. Label the atom diagram below and write out
the definitions of each subatomic particle.
2
Which two particles are found in the nucleus? _______________ and _______________
Atoms are always NEUTRAL particles:
# ____________________ = # ____________________
ATOMIC NUMBER -
How many protons does Sodium have? _____
How many electrons does Sodium have? ____
How many protons does Oxygen have? _____
How many electrons does Neon have? ____
How many protons does Sulfur have? _____
How many electrons does Magnesium have? ____
MASS NUMBER –
How many neutrons does Magnesium have? _____
How many neutrons does Chromium have? _____
How many neutrons does Carbon have? _____
For each element find the number of protons, neutron, electrons, mass number and atomic number.
3
ISOTOPE –
Write in hyphen notation (element name – mass #)
Carbon Isotope Example:
Carbon – 12
has _______ protons and _______ neutrons
Carbon – 14
has _______ protons and _______ neutrons
Isotopic Notation is a way of displaying information for an atom or ion.
Mass number
SYMBOL
Atomic number
Example Write the isotopic notation for an atom containing 5 protons, 6 neutrons and 5 electrons.
Practice Write the isotopic notation for an atom which contains 8 neutrons, has a mass number of
17.
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Average ATOMIC MASS –
Average Atomic Mass = (% isotope #1)(mass of #1) + (%isotope #2)(mass of #2) + . . . . .
NOTE: You must change the percentages to decimals before putting them into the equation.
Example Naturally occurring chlorine is 75.53% chlorine-35 and 24.47% chlorine-37. What is the
average atomic mass?
Practice The element neon consists of three isotopes with masses 19.99, 20.99 and 21.99 amus.
These three isotopes are present in nature to the extent of 90.92%, 0.25% and 8.83% respectively.
Calculate the atomic mass of neon.
Practice The element silver exists in nature as two isotopes, Ag-107 and Ag-109. The accepted
atomic mass of silver is 107.87amu. Which isotope is more abundant?
How do we know the isotopes of the elements and their masses…. A mass spectrometer
Practice: Calculate the average atomic mass of the element whose mass spectrometer data is
below.
Practice: First calculate the percent abundance of each isotope and then calculate the average
atomic mass of this element, finally what element does this represent?
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Calculating % abundances
Example Calculate the percent abundance for each isotope of boron if the average atomic mass
is 10.811 amu and:
Isotope
B-10
B-11
Mass (amu)
10.0129
11.0093
Practice Calculate the percent abundance for each isotope of neon if the average atomic mass is
20.1797 amu and:
Isotope
Mass (amu)
Ne-20
19.992
Ne-22
21.991
Ions
Atoms = contain the same number of _________ as __________. Atoms are ___________.
Atoms ___________ have an electrical charge.
Protons
Electrons
Carbon
Chlorine
Sodium
Calcium
Valence electrons
What are they: ________________________________
What are they involved in: ___________
Neutrons
6
Octet Rule = Atoms tend to _____, _____, or _______ until they have ________ electrons in
their outer energy level.
Charge = the ________ of the atom and the number of _______________
Name this element: __________
How many valence electrons? ______
Will it gain or lose electrons? ______
How many? ____
Charge_______
Name this element: ____________
How many valence electrons? ______
Will it gain or lose electrons? _______
How many? _____
Charge ______
Ions = Do NOT contain the same number of _________ as _________ due to the gain or lost
of ___________. Ions DO have electrical charges.
Protons
Electrons
Neutrons
C-4
Cl-1
Na+1
Ca+2
There are two types of ions:
1) Cations = have more ________ than _________; the ion will have a _____________
charge. __________ and __________ make cations.
2) Anions = have more _________ than __________; the ion will have a
_____________ charge. _______________ make anions.
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Decide what type of ion each of the following are. (Cation or anion)
Type of Ion
Type of Ion
Calcium Ion
Oxide Ion
Nitride Ion
Lead Ion
Potassium Ion
Hydrogen Ion
Bromide Ion
Silver Ion
To name ions:
To name Cations = Ions with a ________ charge.
1) If the metal is Group 1A, 2A, Ag, Zn, Cd, or Al (or hydrogen) just name the
metal
Ex. Ca+2 = ______________
2) If the metal is not listed above use roman numerals to indicate the charge.
Ex. Fe+3 = _____________
To name Anions = Ions with a _________ charge.
1) Write the name of the non-metal
2) Change the ending to –ide
Ex. Cl-1 = ____________
Ion
# of
protons
# of
electrons
Name of
ion
Ion
S-2
Ni+2
Al+3
O-2
Fe+2
Pb+2
N-3
F-1
K+1
Mg+2
Zn+2
P-3
# of
protons
# of
electrons
Name of ion
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Chemical
Configuration
Atomic #
Mass #
# of
protons
# of
electrons
# of
neutrons
30
31
37
Net
Charge
Cl 1
42
17
5
13
+3
26
30
+2
Periodic Table
________________________ arranged the elements by atomic weights and properties. He left gaps
where he predicted the discovery of new elements in his creation of the periodic table. He is
coined the “father of periodic table”
_________________ arranged the periodic table as it is today according to the
_______________ __________.
The arrows represent ________ or ___________
They have similar __________ and ____________
The arrows represent ______________
They do not have ____________ _____________
Indicates the number of ___________ ____________.
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Metals
Nonmetals
Metalloids
Metalloid =
All METALS have several characteristics in
common:
1. ____________________________________
2. ____________________________________
3. ____________________________________
4. ____________________________________
5. ____________________________________
All NON-METALS have (almost) opposite
characteristics:
1. ________________________________________
2. ________________________________________
3. ________________________________________
4. ________________________________________
5. ________________________________________
6. ____________________________________
Remember that the number of protons must equal
the number of __________ in a neutral atom.
# of protons = the _________________
Electrons at each energy level
Level 1: ______eLevel 2: ______eLevel 3: ______e-
Draw the Bohr diagram for the following elements.
Lithium
Magnesium
Boron
Silicon
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Nitrogen
Sulfur
Fluorine
Argon
Valence Electrons
What are they? ______________________________________________________________
What are they involved in? _____________________________
Family Names
How many valence electrons
does each family/group have?
Alkali metals
Alkaline earth metals
Halogens
Noble Gases
Transition metals
How many valence electrons do the following elements have?
________ Sodium
________Xenon
________Aluminum
________Bromine
________Strontium
________Potassium
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What charge will the following groups have?
What is the charge after each element below loses or gains electrons?
Charge
Charge
Calcium
Oxygen
Nitrogen
Magnesium
Potassium
Aluminum
Bromine
Cadmium
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Trends in the periodic table
SHIELDING - a barrier made of ______________ which serves to decrease the pull of the
nucleus on the outer electrons.
Shielding _____________ as you go _________a column because there are more innershell electrons due to more and more shells of electrons.
Ex: There are only 2 shells of electrons in lithium and therefore only ONE INNER
SHELL of shielding, but as you move down the column, cesium has 6 shells of
electrons and therefore 5 INNER SHELLS which serve as shielding.
Shielding is considered to be ____________as you move ___________a period because the number of
inner shells are staying the same.
Ex: Sodium has 3 shells of electrons and therefore 2 INNER SHELLS of electrons of
shielding and chlorine which is in the same period STILL HAS ONLY 3 SHELLS of
electrons and 2 INNER SHELLS of shielding.
Practice: Which has more shielding calcium or barium? _________
Which is has more shielding iodine or chlorine? _________
Nuclear Charge - As the number of _________ increases so does the positive charge of the nucleus. As the
nuclear charge ____________ the attraction between ___________ and ___________ is stronger.
Whose outer electrons have a greater pull from the nucleus?
Sodium
or
Chlorine
Gold
or
Cesium
Lithium
or
Oxygen
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ATOMIC RADIUS - 1/2 the ___________ between the radius of two ________ of an element
Draw the general
trend of atomic
radius.
The size of an atom _______________as you move ______________ a column because:
(1) the atoms have _______ orbits of electrons
(2) shielding is ____________ down the column which means the outermost electrons are not
held as tightly and "roam" out to a bigger diameter.
As you move _____________ a period from left to right, the size of the atom ___________ because:
(1) there are more _____________ in the nucleus (which means it can act as a stronger
magnet) but the nucleus is still pulling on the same number of orbits and there is no
additional _____________ to cut down on the pull of the nucleus.
Practice:
Which atom is larger?
Zr
or
Sn
___________
Why:
Which atom is larger? Li or Cs
_____________
Why:
Put these elements in order of increasing atomic radius?
P, F, As, Rb, Sr
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Ion Size
# of
protons
Cations _________ electrons.
The atomic radius ______________.
Why:
___________________________
# of
electrons
Li
Li+1
Na
Na+1
K
K+1
___________________________
Anions _________ electrons.
The atomic radius ______________.
Why:
___________________________
___________________________
# of protons
F
F-1
Cl
Cl-1
Br
Br-1
Practice: Which would be larger, aluminum atom or aluminum ion?
Why:
Which would be larger, fluorine ion or fluorine atom?
Why:
Which would be larger, oxide ion or sulfide ion?
Why:
# of electrons
15
Isoelectronic = A group of _______ all containing the same number of _____________.
O2-, F-, Na+, Mg2+, Al3+
All of these contain _____ electrons.
The more positive the ion = the ________ the ion
The more negative the ion = the ________ the ion
Practice:
Arrange the following in order of increasing size
Cl-1, Al+3, P-3, Mg+2, Na+1
Arrange the following in order of decreasing size
Mg2+, Ca2+, Be2+, Sr2+