The Periodic Table and Periodic Law

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The Periodic Table and Periodic Law

• Chapter 6
• Section 6.1 and 6.2

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Learning Targets

• 5.19 Know the history of the development of the
  Periodic Law
• 5.15 Understand the arrangement of the Periodic
  Table (s,p,d blocks)
• 5.17 Identify periodic trends based upon group
  and period locations on Periodic Table

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Previously in Chemistry

• Atomic Structure of the atom
• Protons, neutrons, electrons
• Atomic (Z), Mass (A)
• Isotopes same of protons (Z) but different
  number of neutrons (A)
• Neutral Atom protons electrons

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Today in Chemistry

• Ions (protons ? electrons)
• Development of the periodic table
• Organization of the periodic table

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Ions

• Atoms can gain or lose electrons, resulting in
  or charge
• Charge of ion of protons - of electrons
• electrons (e-) protons (p) negative
  charge (anion)
• less electrons (e-) charge (cation)

NOTE greater than,
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• Determine the number of protons, neutrons
  electrons in the following
• 50 2
• Ti
• 22
• 17 2-
• O
• 8

• 50
• Ti
• p22, n28, e20
• 17
• O
• p8, n9, e10

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Development of the Periodic Table

• Late 1700s Lavoisier compiled a list of 33
  elements known at that time
• Around 1870s approx. 70 elements were known
• Dobereiners Triads Organized groups of 3
  elements according to similar densities
  chemical properties
• properties of middle element were average of
  other 2

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continued

• English Chemist John Newland proposed an
  organizational scheme for the elements
• Noticed that elements were arranged according to
  increasing atomic mass
• Elements properties repeated every 8 element
  law of octaves
• Called the repeating properties periodic
• BUT did not work for ALL elements

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continued

• Russian chemist Dmitri Mendeleev designed first
  comprehensive P.T.
• Used 2 criteria to organize
• 1. Increasing atomic mass
• 2. Put elements in same column if chem. phys.
  properties were similar
• Insightful because he predicted right spots to
  place undiscovered elements

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continued

• In 1913, English Chemist Henry Moseley discovered
  that atoms contain a unique number of protons
  called the atomic number
• When elements are arranged according to
  increasing ATOMIC NUMBER, there is a repetition
  in their chemical and physical properties
  Periodic Law

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You need to look at the Periodic Table
horizontally and vertically.

• The vertical sections are called groups or
  families. There are 8 main groups (A)
• The horizontal sections are called rows or
  periods. There are seven main periods

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The Modern Periodic Table

• Representative Elements
• Possess a wide range of chemical and physical
  properties
• Elements 1, 2 AND 13-18
• Transition Elements
• Elements classified as metals, nonmetals, and
  metalloids
• Elements 3-12

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Learn the elements in each of these groups

• Group IA alkali metals
• Group IIA alkaline earth metals
• Group VIIA halogens
• Group VIIIA noble gases

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Metals

• Generally shiny when smooth and clean
• Solid at room temperature
• Good conductors of heat and electricity
• Most are malleable and ductile
• Look at B in column 13, heavy stair step line
  that zigzags down to astatine (At) at the bottom
  of group 17.

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Alkali and Alkaline earth metals

• Alkali metals
• All elements on the left side of the table except
  H
• Group 1 elements
• Li and Na
• Highly reactive, usually exist as compounds
• Alkaline earth metals
• Group 2 elements
• Ca and Mg
• Highly reactive

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Transition and inner transition metals

• 2 sets of inner transition metals
• 1. Lanthanide series
• 2. Actinide series
• Rest of the elements in groups 3 to 12 make up
  the transition metals

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Nonmetals

• Occupy the upper right side of the table
• Generally gases or brittle, dull-looking solids
• Poor conductors of heat and electricity
• Br nonmetal that is a liquid in room temp
• Halogens group 17
• Highly reactive
• Noble gases group 18
• Lasers, neon signs, light bulbs

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Metalloids

• Bordering the stair step zigzag line
• AKA Semimetals
• Have physical and chemical properties of both
  metals and nonmetals
• Si and Ge

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Classification of the Elements

• E config determines the chemical properties of
  an element
• Valence electrons electrons in the highest
  principal energy level of an atom
• Valence electrons are the electrons that are
  involved in the bonds that atoms form
• The group 1 elements have similar chemical
  properties because they have the same number of
  valence electron, s2

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Stuff you know already

• Energy level of an elements valence electrons
  indicates the period on the table in which it is
  found
• For example Li valence electron is in second
  energy level, and Li is found in period 2
• Valence electrons of an element can be found
  using its group number
• For groups 13 18, electrons are TEN less the
  group number

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s, p, d, f blocks

• s-Block elements consists of groups 1 and 2
• p-Block elements consists of groups 13 to 18
• d-Block elements comprise of many of the
  transition metals
• Characterized by a filled outermost s orbital
• f-Block elements comprise of the inner transition
  metals
• Characterized by a filled outermost s orbital

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Do you know what kind of elements tend to form
cations () ?

• Metals
• On the LEFT side of the Periodic Table
• Why? ? easier to LOSE electrons and become stable
  or nobelize
• NOBELIZE most elements want to fill up their
  orbital to become noble gas.
• It can achieve it by stealing or donating
  electrons

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Do you know what kind of elements tend to form
anions (-)?

• Nonmetals
• On the RIGHT side of the Periodic Table
• Why? ? easier to GAIN electrons and become stable
  or nobelize
• NOBELIZE most elements want to fill up their
  orbital to become noble gas.
• It can achieve it by stealing or donating
  electrons

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Lets summarize

• Ions have unequal protons and electrons
• Cation () protons electrons
• Anion (-) electrons protons Ions have unequal
  protons and electrons
• Periodic table organized by atomic number into
  groups (columns) and periods (rows)
• A group identifies how many valence electrons