NAMING BINARY COVALENT COMPOUNDS

1. NAMING BINARY COVALENT COMPOUNDS • The pattern used to name binary covalent compounds is similar to that used to name binary ionic compounds: name = name of least electronegative element + stem of more electronegative element + -ide • In addition to the pattern, the number of each type of atom in the molecule is indicated by means of the following Greek prefixes: • Note: The prefix mono is not used when it appears at the beginning of the name.

2. NAMING BINARY COVALENT COMPOUNDS EXAMPLES • SO2: name = sulfur + di- + ox + -ide = sulfur dioxide • XeF6: name = xenon + hexa- + fluor + -ide = xenon hexafluoride • H2O: name = di- + hydrogen + mono- + ox + -ide = dihydrogen monoxide (also known as water) (Note, the final o of mono- was dropped for ease of pronunciation.)

3. IONIC COMPOUNDS CONTAINING POLYATOMIC IONS • The rules for writing formulas for ionic compounds containing polyatomic ions are essentially the same as those used for writing formulas for binary ionic compounds. • The symbol for the metal is written first, followed by the formula for the negative polyatomic ion. Equal numbers of positive and negative charges must be represented by the formula. • When more than one polyatomic ion is required in the formula, parentheses are placed around the polyatomic ion before the subscript is inserted.

4. COMMON POLYATOMIC IONS

5. EXAMPLES OF IONIC COMPOUNDS CONTAINING POLYATOMIC IONS • Compound containing K+ and ClO3- KClO3 • Compound containing Ca2+ and ClO3- Ca(ClO3)2 • Compound containing Ca2+ and PO43- Ca3(PO4)2

6. NAMING IONIC COMPOUNDS CONTAINING POLYATOMIC ANIONS • The names of ionic compounds that contain a polyatomic anion are obtained using the following pattern: name = name of metal + name of polyatomic anion • Examples: • KClO3 is named potassium chlorate • Ca(ClO3)2 is named calcium chlorate • Ca3(PO4)2 is named calcium phosphate • CaHPO4 is named calcium hydrogen phosphate

7. INTERPARTICLE FORCE SUMMARY • Ionic and covalent bonds represent two of the forces that occur between atomic-sized particles and hold the particles together to form the matter familiar to us. • Other forces also exist that hold the particles of some types of matter together. These include: • metallic bonding, • dipolar forces, • hydrogen bonding, • dispersion forces.

8. TYPES OF MATERIALS • Ionic compounds (e.g. NaCl) are held together by ionic bonds, which are attractive forces that hold together ions of opposite charge. • Polar covalent compounds (e.g. H2O and CO) are held together by dipolar forces, which are attractive forces that exist between the positive end of one polar molecule and the negative end of another.

9. TYPES OF MATERIALS (continued) • Some polar covalent molecules (e.g. H2O) experience hydrogen bonding, which is the result of attractive dipolar forces between molecules in which hydrogen atoms are covalently bonded to very electronegative atoms (O, N, or F). • Network solids are solids in which the lattice sites are occupied by atoms that are covalently bonded to each other (e.g. SiO2 and diamond).

10. TYPES OF MATERIALS (continued) • Metals (e.g. Cu) are held together by metallic bonds, which originate from the attraction between positively charged atomic kernels that occupy lattice sites and mobile electrons that move freely through the lattice. • Nonpolar covalent molecules (e.g. O2 and CO2 – shown below) are only held together by dispersion forces, which are very weak attractive forces acting between the particles of all matter that result from momentary nonsymmetric electron distributions in molecules or atoms.

11. THE BEHAVIOR OF SELECTED PURE SUBSTANCES IN RESPONSE TO HEATING

12. RELATIVE STRENGTHS OF INTERPARTICLE FORCES