empirical formula - the simplest formula we can write. Many compounds may have the same empirical formula

carbohydrates: CH₂O

molecular formula - tells us exactly how many atoms of each element are in a single molecule of that compound. Again, many compounds may have the same molecular formula.

ribose: C₅H₁₀O₅

glucose & fructose: C₆H₁₀O₆ - need structural formulas to tell difference

molecular compounds –consist of only nonmetals:

naming binary molecular compounds:

CO, CO₂, NO, NO₂, N₂O_3, N₂O₄

give number as bi, tri etc. last element (one furthest to right on table) ends in –ide)

These are molecular compounds – composed only of nonmetals

Table 2.3

Ionic compounds – composed of a metal and a nonmetal – may be simple and have only two elements such as salt, NaCl = sodium chloride

or complex with a poly atomic ion such as sodium phosphate Na₃PO₄ where PO₄ is a single ion.

Monoatomic ions – from periodic table, the charge on many ions can be predicted.

figure 2-10

metals = positive

nonmetals = negative

negative charged ion always listed last

do some examples

Polyatomic ions – composed of nonmetals that together carry a charge

Table 2-4

When ionic compounds are formed, the charges must sum up to zero.

Since these compounds involve charges, they are also considered polar. Because of this, water loves to hang around and often sticks very tightly to the solid compounds to form hydrates. In the formula of a hydrate, we indicate the number of waters associated with each ionic unit.

copper (II) chloride heptahydrate = CuCl₂ . 7 H₂O

Acids and bases:

mineral acids and bases are made from ionic compounds that, according to Arrhenius, produce H⁺ or OH^- when dissolved in water.

When dissolved in water, ionic compounds break apart into their component anions and cations. Therefore when an anion has its charge balanced by hydrogens, it is an acid:

nitrate ion: NO₃^- forms HNO₃ = nitric acid

nitrite ion: NO₂^- forms HNO₂ = nitrous acid

what do you notice about naming conventions?

chlorite ion: ClO₂^- forms HClO₂ = chlorous acid

phosphate ion: PO₃^-3 forms H₃PO₄ = phosphoric acid

Table 2.5 exchange a different halogen in for chlorine to show how names change.

Any ionic compound containing hydroxide ion (OH^-) will be a base and is named as per any other ionic compound – sodium hydroxide, etc.