Chemical Bonds, Energy,

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Chemical Bonds, Energy, Chemical Reactions

• Essential Question
• What are the 3 types of chemical bonds
• What are the 3 types of Energy
• What are the 2 types of Chemical Reactions

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Chemical Bonds

• 3 Types of Bonds
• Ionic- one atom donates its valence electron to
  another atom or gains electron from another atom
• Formed between 2 oppositely charged ions
  dissociates in water.
• Covalent- atom shares its valence electrons with
  1 or more atoms
• Strongest type of bond between atoms
• Hydrogen- hydrogen atom covalently bonded to
  another atom is attracted to the partial negative
  charge of nearby oxygen/nitrogen atom that is
  covalently bonded with another atom
• Weakest type of bond only holds molecules
  together

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Example of Ionic Bond
sodium (on the left) loses its one valence
electron to chlorine (on the right),
a positively charged sodium ion (left) and a
negatively charged chlorine ion (right).
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Example of Covalent Bonding
When two chlorine atoms covalently bond to form
Cl2, the following sharing of electrons occurs
Each chlorine atom shared the bonding pair of
electrons
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Example of Hydrogen Bonding
Water has a partial negative charge (-) near the
oxygen atom due the unshared pairs of electrons,
and partial positive charges () near the
hydrogen atoms.
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Cations, Anions, Electrolytes

• Cation is a positively charged ion b/c it donates
  the electron in an ionic bond
• Anion is a negatively charge ion b/c it accepts
  the electron in an ionic bond
• Electrolyte is an ionic compound that breaks
  apart into cations anions in water are
  important b/c
• Control water movement
• Maintain acid/base balance
• Produce nerve impulses

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Polar Nonpolar Covalent Bonds

• Polar Covalent Bonds occur when sharing of
  electrons is unequal gives molecule a partial -
  partial charge
• H20 is a important covalent molecule
• Nonpolar Covalent Bonds occur when the sharing of
  electrons is equal
• Bonds between 2 of the same atoms are ALWAYS
  nonpolar

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Chemical Reactions, Energy, Chemical Energy

• Chemical Reaction- when atoms combine or break
  apart from other substances
• These require Energy or the capacity to do work.
  There are 2 main forms
• Potential NRG is NRG stored by matter due to its
  position
• Kinetic NRG is NRG of matter due to its motion
• Chemical NRG- form of potential NRG stored in the
  bonds of molecules

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Types of Chemical Reactions

• Synthesis Reactions(RXN)- When 2 or more
  atoms/ions/molecules combine to form new and
  larger molecules
• A B ? AB
• 2H2 O2 ? 2H2O
• Decomposition RXN- when a molecule is split apart
• AB ? A B
• CH4 ? C 2H2

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Quiz Tuesday

• Possible Discussion Questions
• Compare/Contrast Polar vs. Non Polar Covalent
  Bonds
• Electrolytes Their Importance to you
• Free Radicals Antioxidants
• Define Atom Atomic Mass
• Draw an Atom Label its parts