Chapter 2 Chemistry of Life part II

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Chapter 2 - Chemistry of Life (part II)

• High School Biology Class

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Atoms Can Bond

• Atoms can join together with other atoms to form
  new substances.
• A compound is a substance made up of the joined
  atoms of two or more different elements.

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Types of Bonds

• Covalent Bond
• Hydrogen Bond
• Ionic Bond

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Covalent Bond

• A bond where two or more atoms SHARE electrons to
  form a molecule.
• (i.e. H2O, CO2, etc.)

Two hydrogen atoms equally share electrons.
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Multiple Bonding

• Single Bond two electrons are shared.
• Double Bond four electrons are shared.
• Triple Bond six electrons are shared.

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Important Facts

• Carbon atoms are the best at bonding because they
  have four electrons in their outer orbit and
  therefore can bond with up to four other atoms.
• Thus, Carbon atoms are essential to life.
• Organic molecules all contain Carbon.

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Hydrogen Bond

• A bond where shared electrons are attracted more
  strongly to one atom than the other.

Two hydrogen atoms and one oxygen atoms share
electrons, but the oxygen attracts the electrons
more.
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Ionic Bond

• A bond where two or more atoms GAIN or LOSE
  electrons in order to form stable energy levels.
• (i.e. NaCl, KBr, etc.)

Sodium (solid) Chlorine (gas) Salt
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Ionic Bond (contd)

• A sodium atom with one outer electron and a
  chlorine atom with seven outer electrons lose and
  gain electrons.

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Any Questions?

• My only advice is to stay aware, listen
  carefully, and yell for help if you need it.
• --Judy Blume