The Periodic Table

1
The Periodic Table

• Elements are arranged in a way that shows a
  repeating, or periodic, pattern.
• Dmitri Mendeleev created the first periodic table
  of the elements in 1869.
• He ordered the 70 known elements by their atomic
  masses and their chemical properties.
• He found that some elements could not be put into
  groups with similar properties and at the same
  time stay in order.

2
Modern Periodic Table

• Later, Henry Moseley carried on the work.
• Moseley put the elements in order of increasing
  atomic NUMBER.
• He found that the position of the element
  corresponded to its properties.
• The modern periodic table shows the position of
  the element is related to
• Atomic number AND
• Arrangement of electrons in its energy levels

3
Atomic Sizes using Periodic Table

• As we move down a group, atoms become larger.
• Larger n more shells larger radius
• As we move across a period, atoms become smaller.
• More protons more effective nuclear charge,
  Zeff
• More positive charge increases the attraction of
  nucleus to the electrons in the outermost shell,
  so the electrons are pulled in more tightly,
  resulting in smaller radius

4
Ionization energy

• Ionization energy of an ion or atom is the
  minimum energy required to remove an electron
  from the ground state of the isolated gaseous
  atom or ion.
• The first ionization energy, I1 is the energy
  required to remove one electron from an atom.
• Na(g) ? Na(g) e-
• Larger ionization energy, harder to remove
  electron.

5
(No Transcript)
6
Periodic Trends in Ionization Energy

• Highest Fluorine
• Ionization energy decreases down a group.
• Easier to remove electrons that are farther from
  the nucleus.
• Ionization energy increases across a period.
• Zeff increases, so its harder to remove an
  electron.

7
Electron Affinity

• Electron affinity is the energy change when a
  gaseous atom gains an electron to form a gaseous
  ion.
• Electron affinity Cl(g) e- ? Cl-(g)
• Ionization energy Cl(g) ? Cl(g) e-

Gain
Lose
8
Electronegativity

• Electronegativity is the ability of an atom in a
  compound to ATTRACT an electron.
• F has the highest electronegativity.
• (She is SO ATTRACTIVE!)

9
Metals

• Metallic character increases down a group and
  from left to right across a period.
• Metal properties
• Lustrous (shiny)
• Malleable (can be shaped)
• Ductile (can be pulled into wire)
• Conduct electricity
• Metal oxides form basic ionic solids
• Metal oxide water ? metal hydroxide
• Metal oxides react with acids to form salt and
  water

10
General Trend Summary
Electronegativity, Ionization Energy, Electron
Affinity
F
Atomic Radius, Metallic Character
Electronegativity, Ionization Energy, Electron
Affinity
Atomic Radius, Metallic Character
Fr
11
(No Transcript)
12
Ionization energy

• Ionization energy of an ion or atom is the
  minimum energy required to remove an electron
  from the ground state of the isolated gaseous
  atom or ion.
• The first ionization energy, I1 is the energy
  required to remove one electron from an atom.
• Na(g) ? Na(g) e-
• The 2nd ionization energy, I2, is the energy
  required to remove an electron from an ion.
• Na(g) ? Na2(g) e-
• Larger ionization energy, harder to remove
  electron.

13
Periodic Trends in Ionization Energy

• Highest Fluorine
• Ionization energy decreases down a group.
• Easier to remove electrons that are farther from
  the nucleus.
• Ionization energy increases across a period.
• Zeff increases, so its harder to remove an
  electron.
• Exceptions Removing the 1st and 4th p electrons

14
Electron Affinity

• Electron affinity is the energy change when a
  gaseous atom gains an electron to form a gaseous
  ion.
• Electron affinity Cl(g) e- ? Cl-(g)
• Ionization energy Cl(g) ? Cl(g) e-

Gain
Lose
15
Electronegativity

• Electronegativity is the ability of an atom in a
  compound to ATTRACT electrons.
• Fluorine has the highest electronegativity.
• Fluorine is SO ATTRACTIVE! (bats eyelashes)

16
Metals

• Metallic character increases down a group and
  from left to right across a period.
• Metals are found to the left of the zig-zag line
  on the periodic table.
• Metal properties
• Lustrous (shiny)
• Malleable (can be shaped)
• Ductile (can be pulled into wire)
• Conduct electricity
• Metals form cations (positive ions)
• This means they lose 1-4 electrons
• Therefore, they are usually found in IONIC
  compounds

17
Nonmetals

• Lower melting points than metals
• Diatomic molecules are nonmetals.
• The seven (7) diatomic molecules are
• Br2 I2 N2 Cl2 H2 O2 F2
• Two or more nonmetals form molecular compounds
  with COVALENT bonds.

18
Trends

• See your book for full explanation.
• Closer to F more
• ELECTRONEGATIVITY
• ELECTRON AFFINITY
• IONIZATION ENERGY
• Closer to Cs more
• METALLIC CHARACTER
• ATOMIC RADIUS
• REACTIVITY