Atomic Bonds Molecules Compounds

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Atomic Bonds MoleculesCompounds
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CHEMICAL COMPOUNDSWhat I will know this week!
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• I will describe . . .
• an ionic bond
• a covalent bond
• and identify molecules
• and write chemical equations

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CHEMICAL BOND
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• FORCE OF ATTRACTION THAT HOLDS
• 2 ATOMS TOGETHER
• The type of bond depends on what the atoms do
  with their valence electrons

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Ionic Bonds
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• IONIC force of attraction between 2 oppositely
  charged ions
• Ionic bonds occur when a metal and a non-metal
  ion react, the metal loses electrons and the
  non-metal gains electrons
• Ions are charged particles that form when an atom
  GAINS OR LOSES electrons

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POSITIVE OR NEGATIVE CHARGE?
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• Atoms that LOSE an electron have a POSITIVE charge

Sodium Atom Sodium Ion (1)
11 e- 10 e- 11 p
11p 12 n 12 n

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POSITIVE OR NEGATIVE CHARGE?
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• Atoms that GAIN an electron have a NEGATIVE
  charge

Chlorine Atom Chloride Ion (-1)
17 e- 18 e- 17 p 17p
19 n 19 n
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Negative ion names
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• Add the suffix ide to the element name
• Examples
• Chlorine Chloride (part of salt)
• Fluorine fluoride (helps prevent cavities)

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How to make an ion

• In a stable atom the number of protons the
  number of electrons
• In an ion the number of protons stays the same
  BUT the number of electrons changes

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Valence electrons
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• Atoms changed to ions tend to lose all valence
  electrons (last energy level) which leaves the
  2nd to last energy level filled.
• Read
• Metals tend to lose valence electrons net
  positive ion cation
• Non-metals tend to gain electrons net negative
  ion anion

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Ion Reactions
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• Sodium Chloride Sodium Chloride
• Table salt Na1 Cl-1 NaCl
• (charges cancel)

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Ion Reactions
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• Metal ions reacting with non-metal ions
• 1. form a neutral compound
• 2. electrons move from one atom to another atom
• 3. an ionic compound results from an ionic bond

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Periodic Table in general
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• Group 1 1 ion
• Group 2 2 ions
• Group 13 3 ions
• Group 15 -3 ions
• Group 16 -2 ions
• Group 17 -1 ion
• Group 14 can be or
• Transition metals vary 1 2 3
• Group 18 (noble gases) cannot be ions

There are exceptions to these
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Covalent Bonds Molecules
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• Covalent bonds occur when two or more non-metal
  atoms share electrons and combine to form a
  molecule
• Molecule a neutral group of atoms held together
  by covalent bonds, it is the smallest particle of
  a covalent compound

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Diatomic Molecules
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• Diatomic molecules are made of 2 covalently
  bonded atoms
• Certain diatomic elements exist only as diatomic
  molecules in nature
• Examples hydrogen, oxygen, nitrogen, chlorine,
  fluorine, bromine and iodine

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Fluorine Diatomic MoleculeSince they share 2
electrons the outer energy level is now full
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Complex Molecules
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• Made of 3 or more covalently bonded atoms
• Carbon is very often the basis for the molecules
• Examples water, carbon dioxide, plastic,
  gasoline body cell molecules such as
  carbohydrates and protein

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Water Molecule complex molecule
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Both the hydrogen And oxygen outer energy
level Is full because the atoms are Sharing
electrons
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