Chapter 4, Section 3

1
Chapter 4, Section 3

• Compound Names
• and Formulas

2
Naming Ionic Compounds

• Model Molecule
• Sodium Chloride
• Cation name regular
• Anion name gets -ide ending

3
Covalent Bonds

• Model Molecule
• Carbon Monoxide
• These compounds are named using prefixes to show
  number of atoms.

4
Prefixes for Covalent Compounds

• 1 Mono
• 2 Di
• 3 Tri
• 4 Tetra
• 5 Penta

• 6 Hexa
• 7 Hepta
• 8 Octa
• 9 Nona
• 10 Deca

5
Transition Metals

• These are the metals on the bridge or short
  part of the periodic table, running along the
  center.
• These metals can have more than one charge.
  Sometimes, for example, iron (Fe) gives up 2
  electrons, and sometimes 3.

6
If it helps,

• Think about some brave Roman soldiers, fighting
  to the death on a bridge - each man wielding a
  metal sword and a metal shield.

7
Roman Numerals

• 1 I
• 2 II
• 3 III
• 4 IV

8
Transition Metals, con.

• So iron can form both FeO and Fe2O3, depending on
  the number of electrons the iron atoms gave up.
  In order to identify which iron oxide youre
  talking about, you have to use Roman numerals to
  indicate the charge of the cation in the compound.

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Iron Oxide

• In FeO, the oxygen has a valence of 6, and so it
  takes two electrons, giving it a 2- charge.
• It gets the two electrons from the one iron atom
  - so the iron atom must have a 2 charge.
• This makes the name iron (II) oxide,
• where the Roman numeral II indicates that the
  charge is 2

10
Iron Oxide

• In Fe2O3, the 3 different oxygen atoms would each
  take 2 electrons, for a total of 6-
• Where did they get them?
• From the 2 different iron atoms. If the total
  number of electrons taken is 6, then the total
  number of electrons given must be 6.
• So gave up 3 electrons each.
• each of the two iron atoms

11
FeI2

• Fe is a transition metal, so it can have more
  than one possible number of valence electrons.
• But Iodine is a halogen, so it definitely has a
  valence of 7, so it will take 1 electron.
• There are two iodines in the formula, and each of
  them must have taken 1 electron, for a total
  charge of 2-
• So it must be iron (II) iodide

12
MnF3

• Manganese (not magnesium!) is a transition metal.
  Flourine is a halogen, (1-)
• If each of the 3 fluorines took 1 electron, the
  manganese atom must have given up 3.
• So its
• manganese (III) fluoride

13
Another Example

• What is the formula for aluminum fluoride?
• Aluminum has 3 valence electrons, for a charge of
  3
• Fluorine, a halogen, has a valence of 7, so it
  wants one more electron, for a charge of 1-
• It will take 3 fluorines to take all 3 of the
  aluminum valence electrons, so the formula will
  be AlF3

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Cross your heart!

• CaCl2

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Al2O3
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Al2O3
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