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We will learn to use the periodic table as tool
Like a calculator in math class
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Properties of Metals Good conductors of heat & electricity—called conductors Shiny Ductile--can be stretched into thin wires
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Properties of Metals Malleable--can be pounded into thin sheets
Corrodes--reacts with oxygen in the air to form new compound
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Properties of Non-Metals
Poor conductors of heat & electricity—called insulators Not ductile or malleable sulfur
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Properties of non-metals
Many non-metals are gases Solid non-metals are brittle --means break easily Dull CARBON
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Another suffix: -oid Suffix -oid means “like” or “resembling”
Examples: humanoid asteroid
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Metalloids Elements that sometimes behave like metals and sometimes not 7 of these
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Properties of Metalloids
germanium Properties of Metalloids Can have properties both metals & non-metals—depending on use semi-conductors Separate metals and nonmetals germanium
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Location of element on periodic table will “tell” us a lot about element
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Metalloids
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Non-Metal
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Metals
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Why are elements #57-102 placed at the bottom of the periodic table?
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Reason for separation- convenience
If table were put together the periodic table would not fit on a single sheet of paper.
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Periodic Table in sections
Red lines
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Periodic Table Arranged in several patterns We will learn many
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Rows Horizontal arrangements of elements 7 Called periods
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Periods 1 2 3 4 5 6 7 6 7
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Columns Vertical arrangements of elements 18 Called groups or families
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Groups or Families 1 18 2 13 14 15 16 17 3 4 5 6 7 8 9 10 11 12
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Family Names a.k.a. Group Names
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Family Names Group 1—Alkali Metals Group 2—Alkali Earth Metals
Group 3-12—Transition metals Group 13—Boron Family Group 14—Carbon Family Group 15—Nitrogen Family Group 16—Oxygen Family Group 17—Halogen Family Group 18—Inert Gases or Noble Gases
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Family Characteristics
Group 1—Alkali Metals (pH greater than 7 which means they are bases) Most reactive group Group 2—Alkali Earth Metals (pH greater than 7 which means they are bases) Group 3-12—transition metals (their electron arrangement can change) Group 13—Boron family Group 14—Carbon family
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Family Names Group 15—Nitrogen family Group 16—Oxygen family
Group 17—Halogens (produce salt) Group 18—Noble gases or inert gases (will NOT react with anything)
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Names of the elements at bottom (remember not GROUP)
Elements are Lanthanides Elements are Actinides Elements make up the Rare Earth Metals
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Cr 24 chromium Reading each block on the periodic table 51.996
Chemical name or Element name Average atomic mass chromium 51.996 Cr Chemical symbol or Element symbol Atomic number 24
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FYI #92, U, is last natural element Every element after #92, U, is synthetic
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Chemical symbols 1, 2, or 3 letters
Used instead of writing chemical name Universal “Language of Chemistry” Style of how letters are written matters Size of how letters are written matters Rules for writing chemical symbols: 1st letter MUST be written uppercase Any following letter MUST be written lowercase No cursive
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What does symbol mean? Use symbols instead of words
H means one atom of hydrogen Rh “ “ “ “ rhodium Cu “ “ “ “ copper Ti “ “ “ “ titanium
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These have same answer. Write something that means “one atom of lithium.” Li What is the symbol for lithium?
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Question: The symbol for thallium is Tl. This is an uppercase t and a lowercase L. How do we know that is an L and not an i?
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Answer #1: Second letter of every symbol is ALWAYS lowercase. If the second letter were an uppercase I that would be violating symbol writing rule. Besides Ti is symbol for titanium. Symbols are NEVER duplicated.
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Atomic numbers Whole numbers—always!!! Never duplicated
Periodic table is arranged by increasing atomic numbers
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Average Atomic mass Measure of how much matter there is an atom or subatomic particles (e-, p+, n0) So tiny—created new unit--atomic mass measured in atomic mass unit (amu) Atomic mass on periodic table are averages*
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Usually decimal number Can be written in parentheses
Average atomic mass Usually decimal number Can be written in parentheses --means atomic mass is estimated Can be duplicated
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Why some atomic masses are estimated?
Some elements are unstable Decompose quickly Measuring mass is difficult Some elements are synthetic --means man-made
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How can I tell the atomic mass of an element from its atomic number?
Question How can I tell the atomic mass of an element from its atomic number?
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Answer: --Atomic mass is usually a decimal number or will be written in parentheses that means the other whole number in the box must be the atomic number
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Now… What we know: What periodic table is
What words on periodic table are What numbers on periodic table are What symbols on periodic table are What classification each element is on periodic table What some of the properties are for each element What are the family names Now…
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Elements within a section have similar atomic structure
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Atoms Abbreviations electron e- proton p+ neutron n0
Smallest particle of element that has properties of that element Made-up of: electrons protons neutrons Abbreviations electron e- proton p+ neutron n0
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Charges of e-, p+, and n0? Electrons= negative e- Protons=positive p+
Neutrons=neutral n0 (neutral means no charge)
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Where are e-, p+ & n0 located?
Electrons—outer limits of atom in area called electron cloud Protons & neutrons—innermost area of atom called nucleus Electron cloud has a negative charge. Nucleus has a positive charge.
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Charge of every atom Neutral Why??? Example: silver 47- (electrons)
47+ (protons) _________ neutral charge
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Atoms Review Electrons --charge of each 1- --located: electron cloud
Protons --charge of each 1+ --located: nucleus Neutrons --no charge/neutral
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FYI: Mass of subatomic particles
Mass of 1 proton = 1 amu Mass of 1 neutron = 1 amu Mass of 1 electron = 1/2000 of an amu --Takes 2000 electrons to = 1 amu --Extremely, extremely, extremely, extremely, extremely, small
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Atomic structure How many protons? --atomic number How many electrons?
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Using atomic mass Round to a whole number; known as an element’s mass number Number of protons and neutrons in nucleus For example: atomic mass mass # bromine
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Atomic mass—mass number
Gold has atomic mass of amu which rounds to 197 197 is number of protons and neutrons in nucleus Gold has 79 protons so remaining particles in nucleus are neutrons 197 (mass number) – 79 (p+) = 118 (n⁰)
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Atomic structure How many protons? --atomic number How many electrons?
How many neutrons? --mass number minus atomic number --mass number minus protons
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Electrons, electrons, electrons
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Electrons Electrons have negative charge and are found in electron cloud in energy levels There are 7 energy levels Valence electrons are the electrons that are the farthest from the nucleus—found in outermost energy level---maximum number is 8 Periodic table will give you this information
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Valence Electrons An element that has 8 valence electrons is “happy”—will not react EXCEPTION: Helium is “happy” with 2 because it has only one energy level and the maximum number of electrons in that energy level is two
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Electrons 1 18 1 2 13 14 15 16 17 2 3 3 4 5 6 7 8 9 10 11 12 4 5 6 7 6 7
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Atomic Structure “Cheats”
Mass number- average atomic mass rounded to a whole number. # p+atomic number #n⁰ mass number minus p+ #e- same as p+ # Ve- ones place of group number with the exception of groups 3-12 which can NOT be predicted Energy level period #
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Periodic Table in orbits
1 * 1 D 2 2 3 3 4 4 5 5 6 6 7 7 6 F 6 7 7
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Electron Configuration
1S² # of e- in that orbit Energy Level Orbit
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Electron Configuration of Ga:
1S²2S²2P⁶3S²3P⁶4S²3D¹º4P¹
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Constructing atomic models
Entire model elements 1 – 20 Model of nucleus for every other element
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Step 1—atomic model Draw circle (representing nucleus) Al
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Step 2—atomic model Write p and n in nucleus Al p n n p
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Step 3—Insert correct values
14 n p 13 This model shows 13 protons and 14 neutrons.
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Step 4—add energy levels*
Circles should be concentric. Al 14 n 13 p Remember: This circle represents the nucleus; it is NOT an energy level. *Can be determined by using periodic table.
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Step 5 – add electrons (proper number & location)
Each energy level holds a specific number of e- P.T. shows you how many Use P.T. as tool!!! Do not attempt to memorize a list of numbers!!!!!!!!!!!!! (Examples given in class) 3rd – 7th energy levels more detail later
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Step 6—add symbol Al 13 P 14 N
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