Why name a compound?Well, for one thing, so you don’t end up with a recipe like this:
Ingredients:
1. 532.35 cm3 gluten2. 4.9 cm3 NaHCO3
3. 4.9 cm3 refined halite4. 236.6 cm3 partially hydrogenated tallow triglyceride5. 177.45 cm3 crystalline C12H22O11
6. 177.45 cm3 unrefined C12H22O11
7. 4.9 cm3 methyl ether of protocatechuic aldehyde8. Two calcium carbonate-encapsulated avain albumen-coated protein9. 473.2 cm3 theobroma cacao10. 236.6 cm3 de-encapsulated legume meats (sieve size #10)
Polyatomic IonsPolyatomic ion: a group of atoms all covalently bonded together that have an overall charge.
Example: carbonate = CO3
2-
This is NOT a +4 carbon and three -2 oxygens; they are bonded into one group, move together as a group, and frequently react together as a group.
Structure:
C
O
OO – –
Polyatomic IonsCommon polyatomic ions (memorize these, including charge):
Chlorate: ClO3
-
Hydroxide: OH-
Nitrate: NO3
-
Carbonate: CO3
2-
Sulfate: SO4
2-
Phosphate: PO4
3-
Ammonium: NH4
+
How to Name a Compound1. Write down the name of the first element.2. Leave some space, and write down the name of the
second element, changing the ending to “-ide”.
(if either the first or second thing is a polyatomic ion instead of a single element, use the name of the group instead)
Examples: H2S hydrogen sulfide
Na2SO4 sodium sulfate
NH4Cl ammonium chloride
FeCl2 iron chloride
How to Name a CompoundMost important question:
Is it IONIC?
(again, the compound type, not the Greek pillar)
NO Will be adding prefixes to name
YES May be adding charge to name
Covalent CompoundsAdd prefixes that say how many of each element there are:
1 = mono 2 = di 3= tri 4 = tetra
5= penta 6 = hexa 7 = hepta 8 = octa
9 = nona 10 = deca
Two exceptions: *The last vowel of the prefix is dropped if it sounds funny with the beginning of the element name.* If the first element would be “mono”, the prefix is dropped.
H2S dihydrogen monosulfideCO2 carbon dioxideP2O5 diphophorous tetroxide
Ionic CompoundsQuestion number 2:
Is the metal one of the ones with a predictable charge?
YES you’re done
Na2SO4 sodium sulfate
AlCl3 aluminum chlorideMgO magnesium oxide
NO Add the charge of the metal in roman numerals after the metal name.
FeCl2 iron(II) chlorideSnO2 tin(IV) oxideAg2SO4 silver(I) sulfate
Why Add the Charge?Based on charge, there is only one combination of sodium and oxygen:
Na2O = sodium oxide
But iron can have different charges:
FeCl2 = iron chloride
FeCl3 = also iron chloride?
So there's no need to clarify forsodium, but there is for iron.
All Together Now
1. Is it ionic ?
Yes No
Add prefixes.2. Does the metal have a predictable charge?
You're done! Use formula to work out charge on each metal atom.Add charge in parentheses after metal name, usingRoman numerals.
Name of first element name of second element (ending with -ide)*
YesNo