ap Chemistry

eriodic TableSummer Assignment Part 2.1: Memorizing element names

This is the periodic table you are provided for the AP exam. What do you notice? What is missing?!

There are NO NAMES ON THIS PERIODIC TABLE!

You have to know the name of elements 1 through 56 as well as Pt, Au, Hg, Pb, Rn, Fr, Ra, U, Pu.

There is also NO KEY! You have to know that the whole number above the element is the atomic number, and

that the number with decimals below the element is the average atomic mass.

You will be quizzed by being given this periodic table and filling out the name of elements 1 - 56 plus Pt,

Au, Hg, Pb, Rn, Fr, Ra, U, Pu.Polyatomic IonsSummer Assignment Part 2.2: Memorizing the Polyatomic Ions

Most of your chemistry knowledge will be obtained by building intuition through effort and practice. However,

some things need to be quickly recalled in order to let you focus on larger chemistry concepts. This large list of

polyatomic ions is one of them. While memorization is an important skill, you will also develop pattern

recognition skills, which you will use throughout the year in various contexts.

Polyatomic ions: Polyatomic = many atoms | ion = charged

Polyatomic ions are charged molecules that are composed of many atoms. You learned about these in

Chemistry, for example, OH– is an ionic molecule formed by an O and H covalently bonded together. OH– is

called hydroxide. Notice that most of them involve oxygen. Remember that oxygen’s oxidation state is -2

(except in peroxide compounds such as H2O2).

-1 ions

HCO3

- bicarbonate HSO4

- hydrogen sulfate (bisulfate)

CH3CO2

NO3

NO2

MnO4

CN-

acetate ClO4

perchlorate

nitrate ClO3

chlorate

nitrite ClO2

chlorite

permanganate ClO- hypochlorite

cyanide OH- hydroxide

-2 ions

CO3

carbonate O2

peroxide

SO4

sulfate CrO4

chromate

SO3

sulfite Cr2O7

2- dichromate

S2O3

2- thiosulfate HPO4

2- hydrogen phosphate

-3 ions

PO4

BO3

3- borate

phosphate AsO4

arsenate

At first glance, the nomenclature (naming system) of the polyatomic negative ions in the table above seems

hopeless. There are several general rules, however, that can bring some order out of this apparent chaos:

●

The name of the ion usually ends in either -ite or -ate. The -ite ending indicates a low oxidation state.

Thus, the NO2

– ion is the nitrite ion. The -ate ending indicates a high oxidation state. The NO3

– ion is the

nitrate ion.

1●

The prefix hypo- is used to indicate the very lowest oxidation state. The ClO– ion is the hypochlorite

●

ion.

The prefix per- (as in hyper-) is used to indicate the very highest oxidation state. The ClO4

– ion is

therefore the perchlorate ion.

●

There are only a handful of exceptions to these generalizations. The names of the hydroxide (OH–),

cyanide (CN-), and peroxide (O2

2-) ions, for example, have the -ide ending because they were once

thought to be monatomic ions, and the name stuck around.

Source: https://chemed.chem.purdue.edu/genchem/topicreview/bp/ch2/names.html#poly

There are a LOT of polyatomic ions. It may sound ridiculous to ask you to memorize so many of them, and you

must do it anyway…

By understanding the why as described above, it can be easier to remember the patterns in nomenclature.

Make a silly mnemonic device, create little tricks in your mind, ask the AP chemistry subreddit, use flashcards,

test yourself, test your friend, find a chemistry youtuber you like, google "how to memorize the polyatomic

ions"... do whatever you need to do to memorize these!

During the first week of class, probably on the first day, you will be quizzed on your ability to recall the

formula of an ion when given the name, and to recall the name of an ion when given the formula.

2-ite vs -ateThe name of the ion usually ends in either -ite or -ate. The -ite ending indicates a low oxidation state. Thus, the

NO2

– ion is the nitrite ion. The -ate ending indicates a high oxidation state. The NO3

– ion is the nitrate ion.

The prefix hypo- is used to indicate the very lowest oxidation state. The ClO- ion, for example, is the

hypochlorite ion.

ion NO2

– NO3

–

name nitrite nitrate

suffix ITE ATE

charge -1 -1

Oxidation state of O -2 -2

Oxidation state of N +3 +5

Rank oxidation states

(higher/lower)

lower highe