Write the formula for Lithium Nitride.

Agenda for Tuesday Jan 11th 1.Review/Practice Ionic Bonds2.Metallic Bonds3.Covalent bonds

Rules for writing Ionic formulas

1. The metal comes first (this does not include hydrogen), non-metal comes second.

2. Find the oxidation number of each element3. The oxidation number of the metal becomes

the subscript number of the non-metal and vise versa.

Lithium nitride:Li1+ and N3- Li3N1 or Li3N

Rules for Naming Ionic formulas

1. Write the name of the positive ion (metal).2. If you have a transition metal then you need to

figure out its charge (remember the compound’s oxidation numbers must equal 0) and put it in roman numerals after the name; e.g. Copper (II). If it is not a transition metal proceed to step 3.

3. Write the root of the non-metal’s name (chlor- for chlorine, ox- for oxygen).

4. Add the ending –ide to the root.

Metallic Bonding

• Composed of closely packed cations• Valence e- are a “sea of electrons”• Attraction between valence e- and cations

Metallic Bonding

• “sea of electrons” model explains physical properties of metals

– Good conductors – e- flow freely– Ductile– malleable– luster

Covalent Bonding

• Nonmetal + nonmetal• share electrons– Can share more than one pair

(double, triple bond)

• Atoms held together by sharing electrons are covalently bonded

Covalent (Molecular) Bonds

• Properties– Molecules– Lower melting and boiling points– Most are liq or gas– Nonconductors– Start to talk about shapes of molecules

Ammonia molecule

Multiple Bonds

• Double and triple covalent bonds– Sharing more than one pair of e-

Carbon dioxideNitrogen

• Triple bonds are stronger than double bonds– More energy needed to break 3 bonds than 2 bonds

Polar and Nonpolar

• Covalent bonding can be:

a) Polar – electrons not shared equallyb) Nonpolar – electrons shared equally

Drawing Covalent Compounds

• Draw Dot structure for each compound• Pair unpaired electrons of each compound• Draw a line where you paired electrons

Prefixes

Number of atoms

Prefix Number of atoms

Prefix

1 Mono 6 Hexa

2 Di 7 Hepta

3 Tri 8 Octa

4 Tetra 9 Nona

5 Penta 10 Deca

Naming Covalent Compounds

• 1st word: Give the prefix designating the number of atoms of the first element present, then write the element’s name.

• 2nd word: Give the prefix designating the number of atoms of the second element present.

• CO2: carbon di• Name the root of the second element.

• CO2: carbon diox• Add –ide to the root of the second element.

• CO2: carbon dioxide (official name)

Practice

• N2O4

• PCl5

• NO

• CCl4• SCl2

• Dinitrogen Tetroxide• Phosphorus Pentachloride• nitrogen monoxide –or nitrogen oxide

• Carbon Tetrachloride• Sulfur Dichloride

More Practice

• Sulfur Hexafluoride • Pentanitrogen

Heptoxide• Diodine tetrachloride• Triastatine Octoxide• Phosphorous

Mononitride

• SF6

• N5O7

• I2Cl4• At3O8

• PN

Bonding

100% ionic 100% covalent polar covalent ionic and covalent

NaCl NaNO3 Cl2

KBr Br2