Chapter 6 – Chemical Bonds Unit 9 Chapter 6 – Chemical Bonds

Some elements combine chemically and no longer have the same properties they did before forming a compound. Atoms form compounds when the compound is more stable than the separate atoms.

Stability in Bonding Noble gases are more chemically stable than other elements because they have a complete outer energy level. Elements that do not have full outer energy levels are more stable in compounds.

A chemical bond is the force that holds atoms together in a compound. Atoms can lose, gain, or share electrons to get a stable outer energy level. A chemical bond is the force that holds atoms together in a compound.

Bonds Atoms bond when their valence electrons interact. Remember – everyone wants to be happy like the noble gases.

Shows each valence electron as a single dot. Examples: Lewis Dot Diagrams Shows each valence electron as a single dot. Examples: Fluorine Carbon Sodium

Connecting the dots You can show how the two elements will combine using the dots. Cl

There are three types of atomic bonds: Ionic Covalent Metallic I did not say atomic bombs

Bonds ionic bonds Between a metal and a non-metal. The metal loses it’s electrons and the non-metal takes the electron from the metal.

Ionic Bonds

The two non-metals share electrons. Bonds cont. covalent bonds Two non-metals The two non-metals share electrons.

bonds cont. metallic bonds – positively charged metal ions are surrounded by a cloud of electrons, the outer energy level held loosely so the electrons can flow easily between the ions. These metals conduct electricity because the outer electrons can easily move around.

Ionic Bonds When an atom gains or loses an electron it becomes charged (no longer neutral) this is called ionization. An ion is a charged atom.

oppositely charged ions Metals become positively charged when they give away valence electrons Non-metals become negatively charged when they gain valence electrons.

Anion Cation Positive ion Made when an atom loses an electron. Negative ion Made when an atom gains an electron. Protons = 3 Electrons = Protons = 9 Electrons = 3 2 10 9

Formed between two non-metals. Is the sharing of electrons Covalent Bonds Formed between two non-metals. Is the sharing of electrons Neither atom gives up valence electrons, they share them.

Covalent bonds form molecules. Atoms may share more than one pair of electrons. Atoms do not always share electrons equally. Polar and non-polar molecules

Polyatomic Ions Compounds with both ionic and covalent bonds. Acts the same as any other ion.

Examples: Polyatomic Ions Ammonium NH4+ Hydroxide OH- Sulfate SO4+2 Carbonate CO3-2 Calcium Carbonate CaCO3

Naming Binary Compounds Coming Soon Naming Binary Compounds