Periodic Table & Atomic
Structure
Do not write what is in blue
What is in red is important
Physical Science
January 2015
Periodic Table History
• Dimitri Mendeleev: Russian, developed the 1st
periodic table, which was arranged by atomic
mass.
• Henry Mosley: English, developed the modern
periodic table, which is arranged by increasing
atomic number & properties.
Basic Arrangement of the Periodic Table
• ↓vertical columns: called groups or families.
Every member of has the same number of
valence electrons.
• Valence electrons: electrons in the outermost
energy level of an atom (determines properties
and how compounds are formed). As you move
from left to right across the periodic table you
increase valence electrons by 1 (excluding the
transition metals) until you reach 8 in the noble
gases. Elements with the same number of
valence electrons have similar properties (due to
reactivity)
• → Horizontal rows: called periods. Each row has
the same number of energy levels.
• Metals are located to the left of the staircase
• Non-metals are located to the right of the
staircase.
• Metalloids follow (create) the staircase.
Basic Arrangement- Fill this
Information out on your Table
Periodic Properties
•
Properties of (most) Metals
– solid at room temperature
– shiny (metallic luster)—good reflectors
– good conductors of heat & electricity
– Flexible( Malleable: able to be hammered into thin sheets
– Ductile: able to be drawn into wire)
•
Properties of (most) Non-metals
– Gases or brittle solids at room temperature
– Dull (earthy luster)
– Do NOT conduct heat or electricity well
– Brittle
•
Properties of Metalloids or Semiconductors: Have properties of both metals and nonmetals.
– They are actually non-metals with some properties of metals such as being able to conduct heat
and electricity under certain conditions. They are often used in computers and calculators.
•
Elements may be:
– Reactive: will react with other elements to form compounds
– Inert: will NOT react with other elements
Exceptions to the Rules
• Mercury, Hg is the only
metal that is a liquid at room
temperature.
• Bromine, Br is the only
non-metal that is a liquid at
room temperature.
• Hydrogen, H is the only
non-metal that is on the left
side of the chart.
Element Groups
• Hydrogen
• Falls in line with group 1 because it
only has one valence electron --although it is not a metal.
• When it gains an electron, it behaves
as a non-metal
• When it loses an electron, it behaves
as a metal
•
http://www.periodicvideos.com/videos/001.htm (03:30)
Element Groups
•
•
•
•
Group 1: Alkali Metals
One electron in outer energy level
Only found in nature as a compound
Most reactive group
•
•
https://www.youtube.com/watch?v=uixxJtJPVXk Alkali Metals
https://www.youtube.com/watch?v=m55kgyApYrY (start at 1min)
Element Groups
•
•
•
•
Group 2: Alkali Earth Metals
Two electrons in outer energy level
Only found in nature as compounds
Very reactive
•
Colored fireworks https://www.youtube.com/watch?v=EbkLp3-o78E
Element Groups
• Groups 3-12: Transition Metals: They are less
reactive than metals from groups 1 & 2.
Element Groups
• Groups 13-16: Mixed Groups
• The groups are “mixed” because they contain
metals, non-metals, and metalloids. Each
group is referred to by the top elements
name.
https://www.youtube.com/watch?v=mzahTEBaF8 (diamonds aren’t forever)
Element Groups
•
•
•
•
Group 17: Halogens
All are non-metals
The word halogen means “salt former”.
Each element has 7 electrons in its outer
energy level.
Element Groups
• Group 18: Noble Gases
• All are non-metals and gases
• They have 8 electrons in their outer energy levels so
they are already stable and do not need to combine.
• They do NOT form compounds naturally….they are
inert.
• http://www.youtube.com/watch?v=QLrofyj6a2s
Noble Gases
•
• https://www.youtube.com/watch?v=ozkyh515pJc
(Nova)
What is an Atom?
• Atom: basic unit of matter.
All atoms have two regions
Nucleus (+ charge)
•
Electron cloud (- charge)
http://www.youtube.com/watch?v=bw5TE5o7JtE (In Search of Giants)
Three Sub-Atomic Particles
Symbol used Location
Proton
Mass
1 amu
+ or p+
Neutron
0 or
Nucleus
1 amu
Around the
nucleus
Negligible
(So small it can be ignored for our
calculations.)
n0
Electron
- or e-
http://www.youtube.com/watch?v=xqNSQ3OQMGI (nova animation of atomic models)
Atomic Arrangement
Finding Atomic Mass
• Atomic Mass Unit (amu): a quantity equal to
one-twelfth the mass of a Carbon -12 atom.
• The # of P+ determines the type of atom.
• The number of p+ = number of e• To determine mass number from the chart,
round the average atomic mass to the nearest
whole number.
• To determine # of Neutrons, subtract the
atomic number from the mass number.
Atomic Number ( # of P+ or # of e-)
4
Beryllium
Be
9.0122
Element Name
Chemical Symbol
Average Atomic Mass
(# of P+ + # of N0)
Complete the chart for Beryllium
Element Name
Number of Protons
Number of Electrons
Atomic Number
Chemical Symbol
Average Atomic Mass
Mass Number
Number of Neutrons
Mass # - Atomic #
Atomic Number ( # of P+ or # of e-)
4
Beryllium
Be
9.0122
Element Name
Chemical Symbol
Average Atomic Mass
(# of P+ + # of N0)
Complete the chart for Beryllium
Element Name
Number of Protons
Number of Electrons
Atomic Number
Chemical Symbol
Average Atomic Mass
Mass Number
Number of Neutrons
Beryllium
4
4
4
Be
9.0122 amu
9
5
Complete Carbon
Element Name
Number of Protons
Number of Electrons
Atomic Number
Chemical Symbol
Average Atomic Mass
Mass Number
Number of Neutrons
6
Carbon
C
C
12.011
Complete Carbon
Element Name
Number of Protons
Number of Electrons
Atomic Number
Chemical Symbol
Average Atomic Mass
Mass Number
Number of Neutrons
Carbon
6
6
6
C
12.011
12
6
6
Carbon
C
12.011
Fill out for the Missing Element
Depending on your Birthday. Compete
the Chart
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January- Lithium
February- Na
March- 39 amu
April- Atomic # 7
May- Chlorine
June- Atomic # 10
July- 14 amu
August- Atomic # 13
September- S
October- Phosphorus
November- 40 amu
December- F
Element Name
Number of Protons
Number of
Electrons
Atomic Number
Chemical Symbol
Average Atomic
Mass
Mass Number
Number of Neutrons
How are Electrons Arranged?
• The electron cloud is located around the
nucleus of the atom.
• The electron cloud is arranged into energy
levels (shells), each of these levels is filled
with orbitals, and electrons are most likely
found in these areas within the electron cloud.
The lowest energy level is closest to the
nucleus.
How are Electrons Arranged?
• As you move away from the nucleus, the
energy levels are capable of holding more and
more electrons.
Energy
level
Maximum # of
electrons
1
2
2
8
3
18
4
32
Bohr Models
• A Bohr model of an atom depicts the number
of electrons within each energy level.
• The energy levels are represented by circular
orbits and the electrons are dots on the orbits.
• You must be able to recognize Bohr models of
elements 1-20.
Now you Try!
• On your blank
periodic table draw
models for elements
#1-18.
Recall
• Valence electon- number of electrons in the outermost shell
• Elements with the same number of electrons in their outer
shell have similar properties
– Ex/ groups 1 elements all react similar because they all
have one valence electrons
• The groups determine the valence electrons
• Groups 1 and 7 have the most reactive elements because they
want to loose or gain an electron rapidly
• Groups 8 is stable because elements in this group have a full
outer shell- they do not want to gain or lose any electrons
Neutral or Charged Ion?
•
•
•
•
•
•
•
•
•
Ionization: When atoms gain or lose electrons
In a neutral atom, # of protons = # of electrons.
So the overall charge is zero.
Ion: a charged atom (# of P+ is different from # of e-)
Losing e- = + charge(cation) (cation- think of the t as a
+ or ca+ion, or cats have paws- form a pawwssitive charge)
Gaining e- = - charge (anion) (anion= a negative ionforms a negative charge)
https://www.youtube.com/watch?v=WFFtdxNYdEs
Metals usually lose e- and form cations (+)
Non-metals usually gain e- and form anions (-)
• Gaining e- makes more neg (-), this forms an
Anion
• Losing e- makes more pos (+), this forms a
Cation
• Mg+2
Lost two electrons
• O-2
Gained two electrons
Lewis Dot Diagrams
• Used to represent valence e-.
• Electrons can be paired or unpaired in the
Lewis Dot Structure.
• Generally, the electrons that are available for
combining into a compound are unpaired.
• Draw the Lewis dot structures for:
• Carbon
Oxygen
Chlorine
Lewis Dot Diagrams
• Complete the worksheet in your own notes!!
• Write the
– Lewis dot structure
– Element name
– Atomic #
– Atomic mass
Isotopes
• The number of neutrons in the nucleus can
vary! 
• These variations are called ISOTOPES.
• Isotope: atoms of the same element with a
different number of neutrons. (Different mass)
How to Calculate Isotopes
• Isotopes are symbolized as follows:
Mass Number
Atomic Number
12
6
C
Carbon -12
• To calculate the # of neutrons in the isotope,
• subtract the atomic number from mass
number.
• The above isotope has 6 neutrons (12 – 6 = 6).