The Chemistry of Life Chapter 2

1
The Chemistry of LifeChapter 2

• The Nature of Matter
• Section 2-1
• Biology I

2
Chemistry

• Study of chemistry begins with the atom
• Atom basic unit of matter
• Means indivisible

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Atom

• Contains subatomic particles
• Proton
• Positive charge
• Neutron
• No charge
• Highest mass
• Electron
• Negative charge
• Constantly in motion and high energy motion keeps
  electrons outside nucleus

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Atom

• Nucleus Center of atom that contains protons
  and electrons
• All atoms are neutral
• P E
• Atomic - number of protons
• Atomic mass protons neutrons

5
Elements and Isotopes

• Element pure substance that consists entirely
  of one type of atom
• Over 100 known
• 12 common in living organisms
• Ex C, H, N

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Isotopes

• Isotope atoms of the same element with
  differing number of neutrons
• Identified by their mass numbers (average)
• All isotopes have the same chemical numbers
• Ex hydrogen, deuterium, tritium

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Radioactive Isotopes

• Unstable nuclei and nuclei break down over time
• Radiation is dangerous, but can be advantageous

8
Chemical Compouds

• Compounds two or more elements combined
  together
• Ex H20, NaCl
• Physical and chemical properties of the compound
  differ from the original elements
• Ex NaCl

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Chemical Bonds

• Atoms do not have the same ability to attract
  electrons
• Due to this, usually one atom in a bond will pull
  the electrons closer to it than the other atom.
• Creates partial negative and positive charges
• Creates van der Waals forces
• Slight attraction that develops between
  oppositely charged regions of nearby molecules.
• Ex Gecko