NAMING COMPOUNDS

CH. 6.3

• We use the word, COMPOUND, when describing an ionic bonded molecule.

• An example: – NaCl is sodium chloride

Elements you should know:

• H = hydrogen

• He = helium

• Li = lithium

• Be = beryllium

• B = boron

• C = carbon

• N = nitrogen

• O = oxygen

• F = fluorine• Ne = neon• Mg = magnesium• Al = aluminum• Si = silicon• P = phosphorus• S = sulfur• Cl = chlorine

• Ar = argon• Ca = calcium• Zn = zinc• Na = sodium• K = potassium• Fe = iron• Cu = copper• Ag = silver• Sn = tin• Au = gold• Hg = mercury• Pb = lead

You will be also given a list of polyatomic ions to use

• What?!

Polyatomic ion =

• a compound that has extra or missing electrons to give the overall compound a charge (+ or -)

• These polyatomic ions behave chemically as if they were a single atom

• EX: OH-

– NO3-

– SO4-

Naming RULES!• Rule #1: If two identical elements

combine, then the name doesn’t change

• examples:– O2 = oxygen

– H2 = hydrogen

– N2 = nitrogen

– F2 = fluorine

– Cl2 = chlorine

– Br2 = bromine

Rule #2 When two elements join and one is a halogen, oxygen or sulfur, the name ends with - ide

• example

• magnesium + oxygen magnesium oxide

let’s practice

• sodium + chlorine • magnesium + fluorine • lithium + iodine • chlorine + copper • oxygen + iron • KBr • LiCl

• CaO• MgS• KF

let’s practice

• sodium + chlorine sodium chloride

• magnesium + fluorine magnesium flourided

• lithium + iodine lithium idodide

• chlorine + copper copper chloride

• oxygen + iron iron oxide

• KBr potassium bromide

• LiCl lithium chloride

• CaO calcium oxide

• MgS magnesium sulfide

• KF potassium flouride

Rule #3 when 3 or more elements combine and two of them are H and O, the name ends with “hydroxide”

• e.g. sodium + hydrogen + oxygen sodium hydroxide

practice:

• potassium + hydrogen + oxygen

• LiOH

• CaOH

• Mg(OH)2

practice:

• potassium + hydrogen + oxygen

• LiOH lithium hydroxide

• CaOH calcium hydroxide

• Mg(OH)2 magnesium hydroxide

Rule #4 When 3 or more elements combine and one of them

is oxygen, the ending is -ate

• e.g. copper + sulfur + oxygen copper sulfate

more practice

• calcium + carbon + oxygen

• potassium + carbon + oxygen

• calcium + sulfur + oxygen

• calcium + oxygen + nitrogen

• AgNO3

• H2SO4

• K2CO3

more practice

• calcium + carbon + oxygen calcium carbonate

• potassium + carbon + oxygen potassium carbonate

• calcium + sulfur + oxygen calcium sulfate

• calcium + oxygen + nitrogen calcilum nitrate

• AgNO3 silver nitrate

• H2SO4 hydrogen sulfate (aka: sulfuric acid)

• K2CO3 potassium carbonate

Some compounds have “unique names”

• H2O water

• CO2 carbon dioxide

• NH3 ammonia

• SO2 sulfur dioxide

How do you know what subscripts to use?

• You need to know what ion the element becomes, based on its location on the periodic table.

• Group 1A (alkali metals) all have 1+

• Group 2A (alkaline metals) all have 2+

• Group 3A (metalloids) have 3+

• Group 4 A tend to form covalent bonds

• Group 5A (nitrogen family) have -3

• Group 6A (oxygen family) have -2

• Group 7A (halogens) have -1

Practice!

• It’s easier to learn by doing!!!