Lesson 49 What is molecule

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Lesson 49 What is molecule ?

• How do we call those particles in a
  non-electrolyte ?
• How do we define molecule ?
• Is molecule a macroscopic or microscopic concept
  ?
• What is the meaning of "atomicity"?
• Are all molecules with more than 1 atom bonded
  together ?

2
How do we call those particles in a
non-electrolyte ?

• The particles in a non-electrolyte are called
  molecules. Unlike ions, they don't carry
  electrical charges.

3
How do we define molecule ?

• By definition, molecule is the smallest particle
  that is stable enough to exist on its own.
• Example Cl2, H2O, Ne, C6H12O6
• Not all particles are stable enough to exist
  isolated on its own e.g. Cl atom, Na atom, K
  ion, MnO4- ion.

4
Is molecule a macroscopic or microscopic concept
?

• Molecule is too small to be seen by naked eyes.
  It is a microscopic concept.

5
What is the meaning of "atomicity"?

• Atomicity is the number of atoms in a molecule of
  an element.
• O2
• 2
• O3
• 3

• P4
• 4
• S8
• 8
• H2O
• undefined, water is not an element

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Are all molecules with more than 1 atom bonded
together ?

• Monatomic / monoatomic molecule
• He, Ne, Ar, Kr
• Diatomic molecule
• HCl, Cl2, O2, N2
• Triatomic molecule
• H2O, O3
• Polyatomic molecule
• C6H12O6 (glucose)
• (CF2-CF2)n (Teflon polytetrafluoroethene)

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Classwork(Do them on your textbook)

• pg201 Q3