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Nomenclature

Nomenclature is the naming of chemical elements and compounds

Memorize the ELEMENTS in GREEN

This is a good useable set of elements to memorize the symbol and name. Do not worry about the atomic number - remember, you will have a periodic table for all exams. The main thing is to know how to match element names to their symbols as in potassium = K. A perfect thing for homemade flash cards.

Now notice the dark blue line that starts just under boron (#5) - that is the transition line between the metals and the non-metals. Everything to the left of that line is a metal (except hydrogen, duh). Everything to the right is a non-metal. Elements bordering the line... for us that's boron, silicon, germanium, arsenic, and antimony (the ones you memorize) are metalloids (aka semiconductors). Why is this important? Because metals and non-metals tend to ionize in opposite ways. Metals lose electrons and become cations (positively charged ions - pronounced CAT·ion) and non-metals gain electrons and become anions (negatively charged ions - pronounced AN·ion). Each group is named in different ways.

Monatomic Cations

These are all metals (except H+). Metals that make only ONE type of cation are just named exactly the same as the metal. All the group 1 and group 2 metals are like this. Na+ is a sodium ion, Ca2+ is a calcium ion. You do NOT try to use a modifier (adjective, prefix, or suffix) to indicate charge. All the group 1 metals make +1 cations and all the group 2 metals make +2 cations. Here are four more to add to the list of "always the same" cations to add:

Al3+, Zn2+, Ag+, Cd2+

The rest of the metals (all transition metals in the d-block) have to have their charge indicated in the name via a roman numeral suffix in parenthesis. This means that Fe2+ is called iron(II) and Fe3+ is called iron(III). Most cations don't go beyond a +4, so you don't have to count too far in roman numerals... although, do know that V4+ is named and written vanadium(IV).

Monatomic Anions

The non-metals gain more electrons and reach noble gas electron configurations which means a full set of s and p orbital (s2p6). The naming is done by replacing the suffix with -ide. So Cl is called chloride and S2– is called sulfide. See the table to learn all of them - but remember that it IS pretty systematic in the naming. Because all the non-metal monatomic anions match noble gas configuration, there are never more than one possible charge. ALL the halogens (group 17) make –1 anions. All the group 16 elements make –2 anions and so on... but only for the non-metals.

Polyatomic Ions

There are also a lot of ions that exist that are made up of 2 or more covalently bound elements. We call them the polyatomic ions. There is a fairly full listing of these in the appendix (section 10.6). To keep things a bit more manageable, I've honed this down to a "shortlist". This is where you just have to go ahead and memorize them. There is some method to the madness and you can learn it. This is a very helpful list and you need to know these polyatomic ions from here on.

Polyatomic Ions (shortlist)

Yes, you need to memorize this set of polyatomic ions: name, formula, and charge.

NameFormula
ammonium NH4+
hydroxide OH
nitrite NO2
nitrate NO3
sulfite SO32–
sulfate SO42–
acetate CH3COO
carbonate CO32–
phosphate PO43–
phosphite PO33–
NameFormula
perchlorate ClO4
chlorate ClO3
chlorite ClO2
hypochlorite ClO
bromate BrO3
iodate IO3
permanganate MnO4
peroxide O22–
cyanide CN




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