1. Section 3: Covalent Bonds

2. Key Terms Covalent Bond – formed when two atoms share electrons
Molecule – a neutral group of atoms joined by covalent bonds
Double Bond – when two atoms share two pairs of electrons
Triple Bond – when atoms share three pairs of electrons
Molecular Compound – a compound that is composed of molecules
Polar Bond – a covalent bond in which electrons are shared unequally
Nonpolar Bond – a covalent bond in which electrons are shared equally

3. formed by electrons being shared, not completely transferred.
Covalent Bonds
formed by electrons being shared, not completely transferred.
The attractions between the nucleus and the shared electrons holds the atoms together as a compound. This type of bond is not as strong as an ionic bond.

4. How Covalent Bonds Form
The force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus for the shared pair of electrons.

5. How Covalent Bonds Form
The oxygen atom in water and the nitrogen atom in ammonia each have eight valence electrons as a result of forming covalent bonds with hydrogen atoms.

6. How Covalent Bonds Form
Double and triple bonds can form when atoms share more than one pair of electrons.

7. Section 3: Covalent Bonds
What are the properties of molecular compounds?

8. Section 3: Covalent Bonds
What are the properties of molecular compounds? (as compared to ionic compounds)
Lower melting point
Lower boiling point
Doesn’t conduct electricity when melted or dissolved in water

9. Section 3: Covalent Bonds
How does unequal sharing of electrons affect molecules?

10. Section 3: Covalent Bonds
How does unequal sharing of electrons affect molecules?
Unequal sharing of electrons causes the bonded atoms to have slight electrical charges.

11. Unequal Sharing of Electrons
Fluorine forms a nonpolar bond with another fluorine atom. In hydrogen fluoride, fluorine attracts electrons more strongly than hydrogen does, so the bond formed is polar.

12. Unequal Sharing of Electrons
A carbon dioxide molecule is a nonpolar molecule because of its straight-line shape. In contrast, a water molecule is a polar molecule because of its bent shape.

13. Polar Bonds
The unequal sharing of electrons because one atom is stronger than the other atom. It makes the atom with the stronger pull slightly negative and the atom with the weaker pull slightly positive. When this happens a polar bond forms. When polar bonds form in molecules one end will become more positive, while the other end becomes more negative. The water has one end that has a more positive charge and one end that has a more negative charge. The water molecules are pulled towards each other.
Describe how the electron dot configuration helps us see how the valence electrons bond, how many they have and the type of bond 13

14. Non-Polar Bonds
-If the electrons are shared equally, then a nonpolar bond is formed. -As in the picture, the carbon dioxide is a nonpolar molecule, having no positive or negative end. -Because of this, the there is little attraction between carbon dioxide molecules.
Describe how the electron dot configuration helps us see how the valence electrons bond, how many they have and the type of bond 14

15. Section 4: Bonding in Metals
How do the properties of metals and alloys compare? 15

16. Section 4: Bonding in Metals
How do the properties of metals and alloys compare?
Alloys are mixtures made of two or more elements, at least one of which is a metal. Alloys are generally stronger and less reactive than the pure metals from which they are made. 16

17. Section 4: Bonding in Metals
How do metal atoms combine? 17

18. Metallic Bonding
Metal atoms combine in regular patterns in which the valence electrons are free to move from atom to atom. 18

19. Section 4: Bonding in Metals
How does metallic bonding result in useful properties of metals? 19

20. Metallic Properties
The “sea of electrons” model of solid metals explains their ability to conduct heat and electricity, the ease with which they can be made to change shape, and their luster. 20