Atomic structure and the periodic table

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Atomic structure and the periodic table

• Atom The smallest particle that has the
  properties of an element
• Element A substance that cannot be broken down
  into simpler substances.
• First proposed by Democritus (atoms)
• John Dalton (schoolteacher) his theory page 105

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Daltons atomic theory

• Every element is made of tiny unique, particles
  called atoms that cannot be subdivided (
  Daltons mistake)
• Atoms of the same element are exactly alike
• Atoms of different elements can join to form
  molecules
• Map the water molecule page 105

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Bohrs model of the atom

• Introduced atom made of a nucleus and electrons.
• Energy levels electrons will only be in certain
  distinct energy levels.
• Copy table on page 106 for main energy levels
  charges and mass and location of each particle of
  the atom

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Atoms Bohrs model
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Atoms can be broken down

• Protons a positively charged subatomic particle
  in the nucleus of an atom
• Nucleus the center of an atom made up of protons
  and neutrons
• Neutrons a neutral subatomic particle in the
  nucleus of an atom
• What is the atomic number equal
  to?_______________

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Electrons

• A tiny negatively charged subatomic particle
  moving around the outside the nucleus of an atom.
• No mass compared to neutrons and protons
• Long way from home
• What is a valence electron _____________________

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Copy the chart here from page 107Copy chart on
page 108What is an s, p, d, f orbital

• What is the minimum number of valence electrons
  
• How many valence electrons does Ne have
• Ar, C, O Na, F, Cl

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Size differences in atoms

• The diameter of a single proton has been measured
  and is found to be 10-15 meters. The diameter of
  a single hydrogen atom in its ground state is
  10-10 meters. So the RATIO of the size of the
  hydrogen atom to the size of the proton is 105.
  Given that ratio you choose a proton -- a marble,
  a baseball, the earth,... and the size of the
  hydrogen atom will be 100,000 time larger.

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Atomic size

• Atoms become larger as we go down a column of the
  periodic table, and they becomes
• smaller as we go across a row of the table.
  because the number of protons in the nucleus also
  increases as we go across a row of the table. The
  nucleus tends to hold electrons in the same shell
  of orbitals more tightly and the atoms become
  smaller.

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Quantum Physics

• electrons exist in probability distributions,
  according to which they are not definitely in any
  specific place at any specific time, but have a
  greater likelihood of being in one place rather
  than another.
• Photons are produced by the transition of
  electrons downward in their orbits. A downward
  transition releases potential energy in the form
  of a light particle, a photon (as seen in an
  emission line).

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s,p,d,f orbital layers

• An s orbital only has 2 electrons. A p orbital
  has six electrons. A d orbital has 10 electrons.
  An f orbital has 14 electrons.
• For instance, scandium, element 21, will have
  all the electrons in the first row and one from
  the second. The electron configuration of
  scandium is 1s2 2s2 2p6 3s2 3p6 4s2 3d1

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Do calculations on page 99 and 100

• There are 65.39 grams of Zn in one mole of Zn.
  There are 130.78 grams of Zn in two moles.

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Covalent radius nm
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Gets crazy

• ---1s2
• ---2s2 ---2p6
• ---3s2 ---3p6
• ---4s2 3d10 ---4p6
• ---5s2 4d10 ---5p6
• ---6s2 4f14 ---5d10 ---6p6
• ---7s2 5f14 ---6d10 ---7p6

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Three dimensional attempts
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Valence electrons

• An electron or electrons in the outermost energy
  level of an atom is called a valence electron.
• Valence electrons are the electrons that combine
  to form new compounds
• An elements reactivity is determined by its
  valence electrons.
• How many valence electrons does carbon have?
  ___________________

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Valence electrons for silicon
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How many valence electrons for

• Lithium ______________
• Chlorine _____________
• Oxygen _____________
• Helium ________________
• Hydrogen __________________

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3.2 Periodic table

• Periodic law properties of elements tend to
  change in a regular pattern when elements are
  arranged in order of increasing atomic number, or
  the number of protons in their atom.
• Atomic number in order is the number of protons
  in the element

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What you must learn

• Know the elements in the first four periods
• Plus Ag, Au, Cd, Hg, Sn, Pb
• Why are groups the same
• What are valence electrons
• Ionic bonding
• Covalent bonding
• Chemical formulas
• Page 116 atomic number and what is atomic mass

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Periods are horizontal rows in the periodic table

• Hydrogen one electron in first s orbital layer.
  Reactive
• Lithium two electrons in first s layer and one
  in second. Page 110 ,114
• Carbon 4 valence electrons in the middle
• Wants to gain 2 or maybe loose 2 or share 2

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Groups (families) vertical columns

• A vertical column of elements in the periodic
  table
• Have the same number of valence electrons
• Similar properties

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Ions

• Group 1 elements very reactive
• Ionization the process of adding electrons to or
  removing electrons from an atom or group of atoms
  
• Ion an atom or group of atoms that has lost or
  gained one or more electrons and therefore has a
  net electric charge

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Cation Anion

• Cation An ion with a positive charge. Usually
  from group 1 and 2
• Looses electrons
• Example Lithium, Na
• Anion An ion with a negative charge.
• Usually from group 16 or 17
• gains electron or electrons
• Example F , Cl, O

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Fluorine Gains one electron Negative ionic
charge of 1
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So what ionic charge would

• Chlorine have ___________
• Manganese have _____________
• Nitrogen have ______________
• Carbon have _______________
• Chlorine ______________
• Calcium _____________
• Neon _____________

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How the structure of atoms differ

• Atomic number the number of _______________in
  the nucleus of an atom
• Periodic table arranged left to right
  by____________________
• Hydrogen atomic number _____
• Uranium atomic number ____________

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Mass number or atomic number

• Mass number the total number of protons and
  neutrons of protons and neutrons in the nucleus
  of an atom
• Electrons not counted relatively no mass
• Mass numbers and atomic mass do not match
  necessarily

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Isotopes

• Isotopes Any atoms having the same number of
  protons but different numbers of neutrons
• Hydrogen has three isotopes protium, deuterium,
  tritium
• Some more common
• Hydrogen average atomic mass 1.00794

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Number of neutrons

• Page118
• Atomic number left side below
• Atomic mass number top left
• Difference the number of neutrons
• So how many neutrons in C-14 ________
• How many neutrons in U -238 _________

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Average atomic mass

• The weighted average of the masses of the all
  naturally occurring isotopes of an element
• Not an even number
• Carbon 12.011
• carbon 12 the most common
• carbon 14 (testing for ages)
• half life of 5,000 years

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3.3 Families of elements

• Two main categories
• Metals and nonmetals
• Metals the elements that are usually good
  conductors of heat and electricity
• Nonmetals the elements that are usually poor
  conductors of heat and electricity

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Alkali Metals Group 1

• Highly reactive metallic elements located in
  Group 1 of the periodic table.
• Loose one electron positive charge ion
• Very reactive not found as an element alone in
  nature
• Form salts

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Alkaline Earth metals Group 2

• The reactive metallic elements located in Group 2
  of the periodic table
• Two valence electrons
• Shells, limestone
• Bones teeth

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Transition metals

• The metallic elements located in groups 3-12 of
  the periodic table.
• Forms metallic bonds
• Metals shiny solids stretched and shaped, good
  conductors of heat and electricity.
• Ductile drawn into wire , malleable bent or
  formed , good elongation, not brittle
• High melting points

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Three types of bonds

• ____________________ An _I________ bond is
  ____________________________________
• __________________ A _ C__________ bond is
  _________________________
• ________________ A _ Me___________ bond is
  _____________________

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Man made elements

• All elements greater than 92 (uranium) are man
  made.
• Most are radioactive
• the nuclei of their atoms are continually
  decaying to produce different elements

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Non Metals

• On the right side of the periodic table
• Gain electrons
• Carbon Organic compounds, fuels

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Name some examples of

• Metals _______________________
• Non metals _______________
• Semiconductors or metalloids _____________________
  __________

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Examples of Carbon compounds
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Non metals

• Dull, brittle, poor conductor
• Not ductile or malleable

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Halogens

• Highly reactive elements located in Group 17 of
  the periodic table.
• Gain one electron
• Chlorine and fluorine are diatomic as are oxygen
  and nitrogen normally
• NaCl table salt ionic compound with alkaline
  and halogen

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Noble gasses

• Unreactive gaseous elements located in Group 18
  of the periodic table
• Inert
• Full valence electrons
• Do not need anything
• Argon, neon, Helium, Xenon a lead balloon, not
  diatomic

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Metalloids or semiconductors

• Six elements boron, silicon, germanium,
  arsenic, antimony, and tellurium are metalloids
  or semiconductors
• Conduct heat or electricity under certain
  conditions
• Chips, diodes, transistors work due to the
  ability to control conductivity

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3-4 Using Moles to count

• Mole The SI unit that describes the amount of a
  substance Large counting unit the mole
• Avogadros constant The number of particles in
  one mole

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Molar mass

• Molar mass is usually the same as its average
  atomic mass.
• Molar mass the mass in grams on one mole of a
  substance
• Molar mass of carbon 12 is 12 grams
• Carbon in nature would be 12.01 grams