Covalent Bonding

Covalent Bonding Sharing is caring

Types of Bonds Review Transfer Electrons Unit Cell Ionic Molecule Covalent Metallic Share Electrons Delocalized Electrons (sea of e-)

In covalent bonding, atoms still want to achieve a noble gas configuration (the octet rule). But rather than losing or gaining electrons, atoms share electrons.

Covalent Bonds When one nonmetal shares one or more electrons with an atom of another nonmetalso both atoms end up with eight valence electrons

But rather than losing or gaining electrons, atoms now share an electron pair. The shared electron pair is called a bonding pair

Naming Covalent Compound

Covalent bonding Makes molecules Specific atoms joined by sharing electrons Two kinds of molecules: Molecular compound Sharing by different elements Diatomic molecules Two of the same atom O2 N2

Diatomic elements There are 7 elements that always form molecules: H2 , N2 , O2 , F2 , Cl2 , Br2 , I2 The –gens (hydrogen, nitrogen, oxygen and halogens) • NEVER FOUND AS SINGLE ATOMS if “alone” • Their names are just the name of the element • Oxygen by itself means O2

1 and 7 Covalent Bond Video

Binary Molecular Compounds Steps to name compounds • Name first element - use entire name • Name second element- change ending to –ide • Prefixes used to indicate numberof each atom d. Only time that no prefix is used is if the first is a one • Examples: CCl4 – As2O3 – carbon tetra chloride di arsenic tri oxide

The Prefixes Mono- monocle Di- Dialogue Tri- tricycle Tetra- Tetris Octa- octopus Penta- pentagon

The first vowel is often dropped to avoid the combination of “ao” or “oo”. CO = carbon monoxide (monooxide) P4O10= tetraphosphorus decoxide SO2= sulfur dioxide (doxide)

Molecular Nomenclature: Examples • CF4 • N2O • SF6 • P2O3 • diphosporus trioxide • IF7 • iodine heptafluoride • carbon tetraflouride • dinitrogen monoxide • sulfur hexafluoride

More Molecular Examples • arsenic trichloride • dinitrogen pentoxide • tetraphosphorus decoxide • AsCl3 • N2O5 • P4O10

Covalent Bonds and Lewis Structures • Octet Rule:All elements will have 8 electrons around it through a combination of shared and unshared electrons. THERE ARE A FEW EXCEPTIONS!!! • Honly needs 2 electrons • Beonly needs 4 electrons • Bonly needs 6 electrons

Covalent Bonds and Lewis Structures • Most covalent bonds involve the sharing of: • 2 electrons (single covalent bond), • 4 electrons (double covalent bond, or • 6 electrons (triple covalent bond).

Covalent Bonds and Lewis Structures (or halogens) H O N C 1 2 3 4 # of bonds * * Element that form the most bonds goes in the middle We are going to use the N.A.S method: N = needed A = available S = shared

Covalent Bonds and Lewis Structures 2 (8) = 16 6 + 6 = 12 16 – 12 = 4 (2 bonds) O2: N = A = S =

Covalent Bonds and Lewis Structures 8 + 8 = 16 4 + 6 = 10 16 – 10 = 6 (3 bonds) CO: N = A = S =

Lewis structures (electron dot structures) show the structure of molecules. (Bonds can be shown with dots for electrons, or with dashes: 1 dash = 2 electrons) • H2HBr • CCl4 • N2

Covalent Bonds and Lewis Structures 8 + 3 (8) = 32 5 + 3 (6) + 1 = 24 32 – 24 = 8 (4 bonds) NO3-: N = A = S =

Covalent Bonding