The Periodic Table of Elements
• Used to keep track of the different elements that are natural & man made
• Mendeleev used atomic mass.• The modern Periodic Table uses
atomic number
Organization
• The elements are arranged by increasing atomic number! (They count up in order!)
• Remember atomic number is the same thing as the number of protons
• The layout of the table (where things are located) is important; the position of things tells us information about specific elements.
# of protons = atomic number
Parts to Know:• Atomic Number: tells us
number of protons in an atom
• The number of protons and the number of electrons in an atom are always the same
• We always assume that atoms are neutral
• The atomic number is specific to each element, like our DNA or fingerprints. We can change the number, but doing so changes the element we have!
Proton = (+) chargeElectron = (-) charge
+6 plus -6 = 00 means neutral charge overall
http://www.middleschoolchemistry.com/multimedia/chapter4/lesson1
Review of each “box”
Mass #
Atomic #Order of electrons
Symbol
# Protons = 17# Electrons = 17# Neutrons = 35 – 17 = 18
Three shells:1st shell has 2 electrons2nd shell has 8 electrons3rd shell has 7 electrons
17 p18 n
…more parts…
• Chemical Symbol: letters that are used to represent the names of different elements
• The first letter is always upper case and the second letter is always lower case
• Ex: Chlorine is always Cl
Mass #
Atomic #Order of electrons
Symbol
Al the symbol for Aluminum.
Its atomic # is 13.This means it has 13
protons.Its mass is 27.
Valence Electrons
• Valence electrons are the electrons located in the LAST energy shell of an atom.
• It is important because it determines how it reacts with other atoms.
11
Families• There are columns on the periodic table
called families.• Each family is named and they tell us the
number of valence electrons an atom has.
• Just like our families, elements in the same family have a lot in common.– Group 17 are used as cleaning products
Electron Configuration
• The bottom of each elemental box has the electron configuration.
• It tells you how many energy shells it has and how many electrons go in each shell.
• Remember: the last number tells you the number of valence electrons.
Families (usually) have the same number of valence
electrons!
This is the electron configuration. There are 4 energy shells and the number of valence electrons is
2.
Rows!
• There are 7 rows on the periodic table, they tell us the number of RINGS an atom has.
Rings = shells = energy levels
Metals• Metals constitute most of the
Periodic Table.• They are on the LEFT of the
staircaseProperties of metals:
1. Malleable (can be hammered)
2. Ductile (can be drawn into a wire)
3. Has luster (shiny)4. Good conductors of heat
and electricity
http://www.middleschoolchemistry.com/multimedia/chapter4/lesson3
Nonmetals
• Nonmetals are located to the RIGHT of the staircase.
Properties of nonmetals:1. Dull2. Poor conductors of heat
and electricity3. A lot of nonmetals are
gasses at room temperature
4. NOT malleable and NOT ductile
5. Brittle (easily smashed into a powder)
SULFUR
Metalloids• Metalloids are in between metals and
nonmetals and are on the staircase.Boron (B), Silicon (Si), Germanium (Ge),
Arsenic (As), Antimony (Sb), and Tellurium (Te)• Properties of metalloids:
1. They are semiconductors2. They have some properties of metals 3. They have some properties of nonmetals
Ex: Te is shiny AND brittle
Antimony
Family 1 / Group 1
• These are called the Alkali Metals.• Highly reactive, shiny, color of silver,
and very soft• Since they are in Group 1, they have
1 valence electron.
Family 2 / Group 2• These are called the Alkaline Earth
Metals.• Since they are in Family 2, they have
2 valence electrons.• They are reactive metals, the color of
silver, and are denser than group 1.
Transition Metals
• Families 3-12 are transition metals because they are transitioning from metals to nonmetals.
• Their valence electrons vary
• They are usually very colorful when combined in compounds, like CuSO4.
Families/Groups 13-16
• They have metals, nonmetals, and metalloids.
• They have the same number of valence electrons.
Key:NonmetalsMetalsMetalloidsCircle the metalloidsX in the metals
Family 17 / Group 17• These are called the Halogens.• They are all nonmetals.• They are very reactive and are poor
conductors of electricity• They usually combine with group 1
to make salts
F
Family 18 / Group 18
• These are called the Noble Gasses.• They are all nonmetals• They are unreactive, colorless,
odorless gasses at room temperature.
http://www.pbs.org/wgbh/nova/physics/hunting-elements.html
• The extra 2 rows are called the Lanthanides and Actinides and are there for a reason!– If they were placed where they belong they
would push the elements in the respective rows/periods OUT of the correct columns!
– Also, their placement would put them in Transition Metals; which means their location is more or less irrelevant, while the placement of elements in Groups 13-18 is significant.
The extra 2 periods
Lanthanides
Actinides
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