1. Chemical Bonding
Created by: Mrs. Susan Dube

2. Chemical Bonds
Chemical bonds are the glue that holds the atoms of elements together in compounds
Chemical bonds differentiate compounds from mixtures
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3. Types of Chemical Bonds
Ionic Bonds
Covalent Bonds
Polar Covalent Bonds
Metallic Bonds
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4. Ionic Bonds
Ionic bonds form when positive ions of one element are attracted to the negative ions of another element
Ions are attracted to one another by electrical attraction of the positive and negative charges
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5. Compounds with Ionic Bonds
Compounds with ionic bonds are very stable
Compounds with ionic bonds have very strong crystals
Ionic compounds form crystals with different regular patterns
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6. Quick Check for Understanding
What are some characteristics of a compound with an ionic bond?
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7. Covalent Bonds
Another way in which atoms can bond together is by sharing electrons.
Nonmetal atoms usually form bonds with each other by sharing electrons.
A pair of shared electrons between two atoms is called a covalent bond.
The shared electrons are attracted to both positively charged nuclei.
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8. Covalent Bonding
The number of covalent bonds an atom can form depends on the number of electrons available for sharing.
Halogen family and hydrogen have only one electron available for sharing.
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9. Covalent Bonding
Group 16 has two electrons available for sharing; therefore, it can form two covalent bonds.
Group 15 has three electrons available for sharing; so they can form three covalent bonds.
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10. Covalent Bonding
Carbon and Silicon in Group 14 have four electrons available for bonding; therefore, they can form four covalent bonds.
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11. Sharing Pairs of Electrons
Sometimes, atoms may share more than one pair of electrons with another atom.
For example, the carbon atom in carbon dioxide (CO2 ) forming double bonds with the oxygen atoms.
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12. Double Bonds
A double bond consists of four (two pairs)of shared electrons.
For example, ethylene, chemical formula C2H4
has two double bonds of carbon bonded with four hydrogen atoms
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13. What is a molecule?
A molecule is a group of atoms held together by covalent bonds.
Most molecules contain two or more elements.
Some molecules contain atoms of only one element, such as H2; N2; O2; F2; Cl2; Br2; I2
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14. Quick Check for Understanding
Answer in your notes!
How does a covalent bond differ from an ionic bond?
What are molecules?
Which compounds can exist as individual elements?

15. Polar Covalent Bonds Copy into notes!
A covalent bond in which the electrons are shared unequally is called a polar covalent bond.
The word polar refers to anything that has two extremes or poles.
Water is the most common polar covalent compound.

16. Comparing Compounds (copy)
Ionic Compounds
Have a regular crystal shape
The ratio of ions give the crystal its shape
Some crystals are rigid and shatter rather than bend when enough force is applied
Covalent Compounds
Exist as individual molecules (ex. O2)
Each molecule has a specific three-dimensional shape called its molecular structure
Shape of the molecule depends on the atoms it contains and the bonds holding it together

17. Covalent, Ionic or Polar Covalent Compound?

18. Quick Check for Understanding
Answer in your notes!
How do polar covalent bonds differ from covalent bonds?
What type of structure do compounds with covalent bonds have?
Which type of compounds have a crystalline structure?
Which compounds can exist as individual elements?

19. Metallic Bonds
Metals bond together by equally sharing electrons in all directions
This equal sharing allows electrons to move easily among the atoms of the metal
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20. Properties of Metallic Compounds
Good conductors of electricity
Electrons in a metal flow through the material carrying the electric current
Good conductors of heat
Have high melting point
All are solids at room temperature except for mercury
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21. Additional Properties of Metals
Metals can be easily shaped by pounding
Can be drawn into a wire
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22. Quick Check for Understanding
How are the metallic bonds unique?
How do metallic bonds affect the properties of metals?
What are some characteristic properties of metals?