Chemistry Language - Formulas And NomenclatureBefore you can begin to name compounds you must first learn the names of the most common elements. The best way is to prepare a set of flash cards, and drill yourself until you know the symbols and names (including correct spelling) flawlessly.

Element Symbol Element Symbol Element Symbol

Hydrogen H Flourine F Chlorine Cl

Bromine Br Helium He Sodium Na

Potassium K Silver Ag Lithium Li

Magnesium Mg Calcium Ca Tin Sn

Boron B Aluminum Al Iron Fe

Iodine I Carbon C Silicon Si

Nickel Ni Lead Pb Nitrogen N

Phosphorus P Copper Cu Barium Ba

Oxygen O Sulfur S Zinc Zn

Chromium Cr Neon Ne Argon Ar

Krypton Kr Xenon Xe Cobalt Co

Manganese Mn Silver Ag Gold Au

Strontium Sr        

At first thought, it may seem difficult to learn the formulas and names of the hundred or so compounds you will encounter in a first year chemistry course. Actually, it is not very difficult if you follow a few systematic rules, which you will need to memorize.

Only UPAC’s names and chemical symbols are allowed during the quiz and exam. No common names are acceptable.

Example I

Chemical Symbol Common Name UPAC's Name

H2O2 Hydrogen Peroxide Dihydrogen Dioxide

H2O Water Dihydrogen Monoxide

K2CO3 Potash Potassium Carbonate

Example II

Correct Symbol Incorrect Symbol

Al  

Mg  

Na  

Cl  

NaCl NaCl-

Example III

Name Correct Symbol Incorrect Symbol

Sulfur Trioxide SO3 SO3-2

I. BINARY COMPOUNDS COMPOSED OF TWO NONMETALS

Binary compounds are composed of atoms of two different elements. One type of binary compound is composed of two nonmetals and is named by using the elemental name for the first element followed by the name of the second element with its ending changed to "IDE". A prefix is added to each name to indicate the number of atoms of each element in the molecule. The mono prefix can be eliminated if it refers to the first element in the name.

Number of Atoms Prefix Number of Atoms Prefix

1 mono 5 Penta

2 di 6 Hexa

3 tri 7 Hepta

4 tetra    

Example: Name SO2

Use the elemental name for the first element - sulfur (a prefix is not used since we drop a mono at the beginning of the name) and then use the root of the second element name "ox" followed by “ide” and preceded by “di” to indicate the presence of two oxygen atoms - dioxide. The correct name for SO2 is sulfur dioxide. The following examples will illustrate some common compounds of this type:

NO2    nitrogen dioxide N2O4         dinitrogen tetroxide CO    carbon monoxide

Notice in the name "tetroxide" the "a" from tetra is omitted, and in the name "monoxide" the "o" from mono is omitted. 

DRILL I (Note: Answers are given at the end of this handout) 

I. Name the following compounds. (correct spelling is required) 

1. SO2 3. P2O5 5. ICl

2. CCl4 4. ClO 6. SF6

II. Write the correct chemical formulas. 

1. nitrogen trichloride 3. oxygen difluoride

2. dinitrogen pentoxide 4. phosphorus pentachloride

DO NOT PROCEED TO NEXT SECTION UNTIL YOU HAVE THOROUGHLY MASTERED PREVIOUS SECTION 

II. BINARY COMPOUNDS OF A METAL AND A NONMETAL (Binary Salts) 

A second type of binary compound is composed of a metal and a nonmetal. It is named by first naming the metal ion and then the nonmetal ion. As illustrated below, the name of a metal ion is generally the same as the name of the element. Nonmetal ions are named by changing the ending of the element's name to "IDE".

Certain metals tend to form two common ions of different charge. In this case, the charge is indicated using Roman Numerals as shown in Table I below. As an alternative, the ion with the higher charge is named using an "IC" ending and the ion with the lesser charge receives an "OUS". In this second system, the original Latin stem names are often used.

DO NOT USE PREFIXES.

TABLE I CATIONS

Representative Elements (Group A) Transition Metals (Group B)

Group IA

Alkali Metals  

H+ hydrogenLi+ lithiumNa+ sodiumK+ potassium

Fe2+ iron(II) or ferrousFe3+ iron(III) or ferricCu1+ copper(I) or cuprousCu2+ copper(II) or cupric

Group IIAAlkaline Earths

Pb2+ lead(II) or plumbous

Mg2+ magnesiumCa2+ calcium

Pb4+ lead(IV) or plumbicSn2+ tin(IV) or stannic

Group IIIA Sn4+ tin(IV) or stannic

Al3+ aluminumHg2

2+ mercury(I) or mercurousHg2+ mercury(II) or mercuric

 Ag+ silverNi2+ nickelZn2+ Zinc

Nonmetal ions are named using the stem of the element's name and changing the ending to "IDE". 

TABLE II ANIONS

F- fluoride O2- oxide N3- nitride

Cl- chloride S2- sulfide P3- phosphide

Br- bromide        

I- iodide        

H- hydride        

A few of the polyatomic (more than one atom) ions have names that are similar to their monatomic counterparts. These are: CN-, NH4

+ ,  

 OH-.

TABLE II POLYATOMIC IONS

NH4+ ammonium CN- cyanide OH- hydroxide

When polyatomic ion is used in writing the chemical formula of the compound more then once, place the polyatomic ion inside the parenthesis and then use the subscript that indicate the number of the polyatomic ions necessary to balance the charge of cation

We combine the metal ion with the nonmetal ion in such a way that the sum of the positive and negative charge is zero, or such that the resulting compound is neutral.

Example 1: Let’s write the formula for potassium bromide by using the charges on its constituent elements. Place the element with the positive charge first followed by the element with the negative charge. The charge on the potassium ion is 1+ and the charge on the bromide ion is 1-.

Since the sum of +1 and -1 is zero, the correct formula for electrically neutral compound sodium chloride is KBr.

Example 2: Write the formula for magnesium fluoride. The charge on a magnesium ion is 2+. Therefore, two fluoride ions are required to make a neutral compound.

Mg2+ + 2F-  = MgF2

   +2 + 2(-1) = 0

Example 3: Write the formula for aluminum oxide. The charge on the aluminum ion is 3+ and the charge on the oxide ion is 2-.

Because +3 and -2 does not equal zero, AlO is not the correct formula. By inspection, it can be seen that 2 atoms of aluminum would give a total of 6 positive units and that three atoms of oxygen would give 6 negative units.

2Al3+ + 3O2-  = Al2O3                              2(3+) + 3(2-)  = 0

Since the sum of +6 and -6 is zero, the correct simplest formula for aluminum oxide is therefore Al2O3.

Some examples of naming binary salts are:

NaCl       sodium chlorIDE KBr         potassium bromIDE CaI2       calcium iodIDE LiF          lithium fluorIDE

DRILL II

I. Name the following compounds: (correct spelling is required) 

1. MgO 6. Ba3P2

2. K2S 7. LiH

3. FeCl3 8. Mg3N2

4. AgI 9. CaBr2

5. Ca(OH)2 10. Cu2S

II. Write the correct chemical formulas

1. calcium nitride 6. lithium phosphide

2. aluminum oxide 7. ammonium chloride

3. sodium cyanide 8. barium hydride

4. potassium hydroxide 9. copper(II) sulfide

5. tin(IV) or stannic bromide 10. iron(II) or ferrous iodide

DO NOT PROCEED TO NEXT SECTION UNTIL YOU HAVE THOROUGHLY MASTERED PREVIOUS SECTION

III. TERNARY SALTS

Ternary compounds are composed of three or more elements. Ternary salts are generally composed of a metal cation and an anion that consists of a group of nonmetals rather than just one. These negative ions are often called polyatomic ions. Examples of polyatomic ions are given in Tables IV and V shown below. In general, when the central atom of a polyatomic ion is bound to a higher number of oxygens, the ion name will end with "ATE". If the central atom is bound to fewer oxygens, the ending will be "ITE". To name ternary salts, name the metal cation first, and then the anion.

DO NOT USE PREFIXES.

When polyatomic ion is used in writing the chemical formula of the compound more then once, place the polyatomic ion inside the parenthesis and then use the subscript that indicate the number of the polyatomic ions necessary to balance the charge of cation 

TABLE IV Some Polyatomic Ions

C2H3O2- acetATE CO3

2- carbonATE PO

NO3- nitrATE SO4

2- sulfATE MnO

NO2- nitrITE SO3

2- sulfITE CrO

    S2O32- thiosulfATE Cr

TABLE V

ClO- HYPOchlorITE BrO- HYPObromITE IO-

ClO2- chlorITE BrO2

- bromITE IO2-

ClO3- chlorATE BrO3

- bromATE IO3-

ClO4- PERchlorATE BrO4

- PERbromATE IO4-

Some examples of ternary compounds are:

+1 - 1 = 0    

NaC2H3O2 NaC2H3O2 sodium acetATE

The charge on the ion gives the combining power of the ion taken as a unit.

2(+1) - 2 = 0    

Na2CO3 Na2CO3 sodium carbonATE

+2 + 2(-1) = 0    

Ca(ClO2)2 Ca(ClO2)2 calcium chlorITE

2(+3) + 3(-2) = 0    

2Al+3 + 3SO4-2 Al2(SO4)3 aluminum sulfATE

DRILL III

1. Name the following compounds (watch your endings)

1. Ca3(PO4)2 8. Cu(C2H3O2)2 15.

2. KNO3 9. KCN 16.

3. BaCO3 10. Na3PO4 17.

4. LiBrO2 11. K2SO4 18.

5. MgSO3 12. Fe(BrO)3 19.

6. Mg(IO4)2 13. AgClO3 20.

7. NaIO3 14. SnSO4  

II. Write the correct formulas for the following compounds:

1. lithium hypobromite 5. aluminum phosphate 9. magnesium chlorate

2. tin(II) nitrate 6. iron(III) sulfite 10. lithium acetate

3. sodium carbonate 7. copper(II) phosphate    

4. ammonium sulfate 8. potassium iodite    

DO NOT PROCEED TO NEXT SECTION UNTIL YOU HAVE THOROUGHLY MASTERED PREVIOUS SECTION 

IV. BINARY ACIDS - The water solutions of compounds composed of hydrogen and a nonmetal 

RULE: Acids composed of hydrogen and a nonmetal are named by putting the prefix HYDRO before the root of the name of the nonmetal and adding the suffix IC followed by the word ACID. 

For example: When hydrogen chloride (HCl) is dissolved in water, we get hydrochloric acid.

HF(aq) HYDROfluorIC acid

HC1(aq) HYDROchlorIC acid

HBr(aq) HYDRObromIC acid

HI(aq) HYDROiodIC acid

H2S(aq) HYDROsulfurIC acid

NOTE: The formulas of binary acids must be followed by (aq). The (aq) means aqueous or dissolved in water. Without the (aq) it would represent a gas. For instance, HCl is hydrogen chloride gas.

V. ACIDS CONTAINING OXYGEN - Compounds of hydrogen and a polyatomic ion (with oxygen present)

RULES:

1. If there is only one oxygen acid, the name is that of the characteristic element followed by the suffix IC.

2. If there are two oxygen acids, the name of the one with the larger number of oxygen atoms ends in IC, and the name of the one with the smaller number of oxygen atoms ends in OUS.

3. If there are four oxygen acids, like the oxyacids of the halogen family, the acid with the greatest number of oxygens is designated by the prefix PER- and suffix -IC, the one with the next fewer oxygens has the suffix -IC, the one with the next fewer has the suffix –OUS, and the fewest oxygens acid is designated with the prefix HYPO- and the suffix -OUS.

For example:

HNO3 is nitrIC acid HBrO is HYPObromOUS acid

HNO2 is nitrOUS acid HBrO2 is bromOUS acid

H2SO4 is sulfurIC acid HBrO3 is bromIC acid

H2SO3 is sulfurOUS acid HBrO4 is PERbromIC acid

HC2H3O2 is acetIC acid H3PO4 is phosphorIC acid

NOTE: Ternary acid formulas are not usually followed by (aq). It is assumed that they are dissolved in water.

DRILL IV

I. Name each of the following: 

1. H2S (aq) 5. H3PO4

2. HC2H3O2 6. HI(aq)

3. HBrO 7. HIO3

4. HF(aq) 8. HBrO2

II. Give the chemical formula of each of the following:

1. nitrous acid

2. hydrobromic acid

3. perbromic acid

4. iodous acid

5. chloric acid

DO NOT PROCEED TO THE NEXT SECTION UNTIL YOU HAVE THOROUGHLY MASTERED THIS SECTION.

VI. ACID SALTS

When a metal replaces one or more hydrogen atoms of an acid, acid salt is formed. To name such salt, we have to identify the number of remaining number of hydrogen atoms in the salt using appropriate prefix ( see page 1).

For example:

H3PO4 is phosphoric acid NaH2PO4 is sodium Dihydrogen phosphate Na2HPO4 is sodium MONOhydrogen phosphate Na3PO4 is sodium phosphate

If the acid contains only two hydrogen atoms, then only two acid salts are possible. These salts could be named by the method described above, but a most common method used by chemists, is to add prefix bi to the name of the anion.

For example:

H2CO3 is carbonic acid NaHCO3 is sodium MONOhydrogen carbonATE or sodium BIcarbonATE Na2CO3 is sodium carbonATE 

VII. DIATOMIC MOLECULES

Seven elements exist naturally as diatomic molecules. They are named by identifying the element preceded by the word "molecular".

Examples:

O2  - molecular oxygen H2  - molecular hydrogen

I2    - molecular iodine F2   - molecular fluorine

Cl2  - molecular chlorine Br2  - molecular bromine

N2   - molecular nitrogen  

VIII. HYDRATES SALTS

Some ionic salts are hydrated, chemically bound with water molecules. These water molecules are called waters of crystallization. In naming a specific hydrated salt, first name the ionic salt according to all rules learned in the above sections, then use the appropriate prefix to indicate the number of water molecules, and finally add the term “hydrate”. For example, MgSO4 . 7H2O has seven waters of crystallization per one mole of magnesium sulfate. The correct name of this compound is magnesium sulfate heptahydrate. 

VIII. PRACTICE QUIZ

1. Give the correct name of each of the following.

a. KClb. Na2CO3

c. CCl4

d. PBr3

e. NaNO2

f. ZnSO3

g. KIO4

h. NiSi. Li3Nj. Cu(OH)2

2. Give the chemical formula of each of the following:

a. sodium oxideb. iron(II) phosphatec. dinitrogen monoxide

d. potassium acetatee. barium hypochoritef. calcium phosphideg. molecular oxygenh. silver nitratei. ammonium sulfatej. magnesium cyanide

ANSWERSThe Language of Chemistry

Equations using symbols and formulae

We can use the chemical symbols and formulae to construct chemical equations for the reactions we have met in the tutorials.

Example I :

The first step is to write the correct formulae:

Unbalanced equation H2S O2 S H2O

The equation is not balanced. Have you noticed that there are two oxygen atoms on the reactants' side of the equation and only one on the products' side?

Look at the image equation. You will see that we need two hydrogen sulphide molecules, two sulphur atoms and two water molecules. So we need to balance the equation. This is achieved by placing a whole number in front of the symbol or formula. Never try to balance the equation by changing a formula in some way.

Balanced equation 2H2S O2 2S 2H2O

Congratulations! You have written your first chemical equation using symbols and formulae. Before you work through some more examples just check again that you have the same number of each type of atom on both sides of the equation.

Remember:

"Matter can neither be created nor destroyed by chemical means"

Example II :

The first step is to write the correct formulae:

Unbalanced equation

Fe HCl FeCl2 H2 

Balanced equation

Fe 2HCl FeCl2 H2 

Before you work through some more examples just check again that you have the same number of each type of atom on both sides of the equation.

Example III :

The first step is to write the correct formulae:

Unbalanced equation

Ca HNO3 Ca(NO3)2 H2 Balanced equation

Ca 2HNO3 Ca(NO3)2 H2 

Before you work through some more examples just check again that you have the same number of each type of atom on both sides of the equation. Everything in brackets () is multiplied by the number outside the brackets. In this case the number of oxygen atoms in calcium nitrate is 3x2 = 6. The number of nitrogen atoms is 1x2 = 2.

Example IV :

The first step is to write the correct formulae:

Unbalanced equation

Cu(OH)2 HNO3 Cu(NO3)2 H2O

Balanced equation

Cu(OH)2 2HNO3 Cu(NO3)2 2H2O

Before you work through some more examples just check again that you have the same number of each type of atom on both sides of the equation. Everything in brackets () is multiplied by the number outside the brackets.

xample V :

The first step is to write the correct formulae:

Unbalanced equation

KOH H2SO4 K2SO4 H2O

Balanced equation

2KOH H2SO4 K2SO4 2H2O

Before you work through some more examples just check again that you have the same number of each type of atom on both sides of the equation.

Equation 1:

Unbalanced equation

.FeH

2SO4

.

FeSO4

.H2

Balanced equation

.FeH

2SO4

.

.FeSO4

.H2

Equation 2:

Unbalanced equation

Al HCl .AlCl3 ..H2

Balanced equation

2Al 6HCl 2AlCl3 3.H2

Equation 3:

Unbalanced equation

.CaO HNO3 .Ca(NO3)2 .H2O

Balanced equation

CaO 2HNO3 Ca(NO3)2 H2O.

Equation 4:

Unbalanced equation

Al2O3 H2SO4 .Al2(SO4)3 H2O

Balanced equation

Al2O3 3H2SO4 Al2(SO4)3 3H2O

Parlez vous la chimie?   Do you speak chemistry?

Instead of teaching a set of nomenclature rules, which is the normal approach, I'd like to approach your learning of chemistry nomenclature in a way similar to learning a foreign language.

The picture here is of the Louvre Museum in Paris. If you were to move to Paris, you would begin learning the language little by little by listening. In other words you could begin to learn a

few words that gives you some idea of what is being said. For example, if you hear "we", you learn that is the French word "Oui" meaning yes. Even if you didn't understand anything else, you would at least know that someone was agreeing with someone else.

In chemistry you don't even need a whole word, but just a syllable to gain some valuable information. For example, you were walking by these two guys and you heard part of the conversation:"When you mix ___ium  ___ide with the ___ide ion the solution turns yellow."

The ending of "ium" tells you that they are probably talking about a metal (like sodium, calcium, potassium, etc.). There are only three exceptions: "helium" and the heavy

isotopes of hydrogen: deuterium & tritium.

The syllable of "ide" tells us that this is a compound made up of only twoelements. For example, "carbon dioxide." Notice that is made up of just two elements, carbon and oxygen.

The exception is if you hear "___ide ion" That means it's a negative ion of some element. For example, chlorine that has gained an electron to become an ion is called a chloride ion and not a

chlorine ion. Positive ions don't use the "ide" ending.

NaCl, CaO, CaCl2, N2O, CO2, KBr, P5O10

Sodium chloride, calcium oxide, calcium chloride, dinitrogen oxide, carbon dioxide, potassium bromide, and pentaphosphorus decaoxide.

Even if you don't know the names of the compounds on the left, you now know they all end in "ide" because each are a combination of two elements. There can be more than two atoms, but only two elements. The only two exceptions I can think of is "hydroxide" and "cyanide" compounds, such as sodium hydroxide (NaOH) and sodium cyanide (NaCN) .

Notice that these have 3 elements. Again, "ide" usually means there's just two elements combined.I'll show you how valuable this little syllable is.

Let's say you and a friend overhear a conversation. Later the FBI interview both of you saying the people you heard were suspected terrorists. The FBI believe they are shipping a dangerous chemical.

You did hear some chemical names being mentioned. Your

friend says he heard "sodium" followed by a word that sounded like "chlorine". You also heard "sodium" but don't remember "chlorine" being said, but you are absolutely sure you heard "ide" at the end of the second word's name.If the word "sodium" is heard by itself, then they are most likely talking about sodium metal. This is very dangerous. In contact with water, it will explode.

The word "chlorine" by itself is refering to toxic chlorine gas. In World War I, chlorine gas was released to kill enemy soldiers.

So the words, "sodium, chlorine" could easily mean that the terrorists have both sodium metal and chlorine gas. These are potent and deadly chemicals.

However, since you heard "ide", this changes the whole meaning. Instead of "sodium, chlorine," the words must have been "sodium chloride," which is table salt. Remember the "ide" means this is a compound made from two elements, in this case sodium and chlorine. Individually sodium and chlorine are very reactive and dangerous; however, once they combine, they are safe and good on french fries. So cancel the terrorist alert.

If you have high blood pressure, the doctor is apt to tell you to reduce your intake of sodium chloride (table salt) and instead use potassium chloride.

One of these bottles contain just what you need to prevent a heart attack; unfortunately, instead of the compound being written out as "potassium chloride," it is written as a formula. Both of these elements have potassium and chlorine atoms. Again, "ide" is the

clue that the correct bottle is the left one because it has just two elements. The right bottle has 3 elements. It's name is potassium chlorate. If you were to cook with this kind of salt, your food would likely explode. So you see, there's a big difference between ending with "ide" or with "ate".

Learning a language means paying attention to patterns. Let's say below is what you see written:

NaCl, KBr, CaF2

You recognize the elements as sodium, chlorine, potassium, bromine, calcium, and fluorine. Now you hear someone read the compounds outloud as, "sodium chloride, potassium bromide, calcium fluoride." You see a pattern. The first element is read as is, the second element's name

is shortened and the suffix "ide" is added.Here's a list of the element names: lithium, chlorine, magnesium, oxygen, sodium, fluorine, calcium, and chlorine. Try naming the compounds to the left.

To see the answer, roll cursor over the image.When learning a language, you often encounter things that seem inconsistent. Notice the discrepancy between how these compounds indicate the number

of atoms. Some compounds do and some don't. Can you see a pattern here? (roll cursor over image for answer)All elements above the yellow stair-step line are non-metals. Whenever any two combine, we need to indicate how many of each are present. The reason for this is that there's often several possibilities. For example, nitrogen and oxygen combine with each other in various numbers, so we can't just say "nitrogen oxide" because that wouldn't identify the

various compounds.

NO, N2O, NO2, N2O3

Notice that these four compounds of nitrogen are called: nitrogen oxide, dinitrogen oxide, nitrogen dioxide, and dinitrogen trioxide.

At this point, you would conclude that "di" means two and "tri" meansthree.When you learn a language, one of the first things you learn is how to count. In chemistry, we use Greek to count.

1= mono (mono isn't used much. 1 is understood)2 = di

3 = tri4 = tetra5 = penta6 = hexa7 = hepta8 = octa9 = nona10 = decaThese seven non-metals usually form toxic compounds. So if you ever hear these spoken or see them written, take notice.

Most end with the syllable "ide" and they use the Greek prefix to indicate the number of atoms. For example, the last one says, "phosphoru

strichloride". Ammonia could be called "nitrogen trihydride" but the ammonia is so well known, that no one says the full name.

Cl2O7

dichlorine heptaoxide (heptoxide)

N2O4

dinitrogen tetraoxide (tetroxide)

PI3

phosphorus triiodide

We now have some nomenclature rules about naming compounds that are made of two different non-metals. 

1. The first element is written as. If more than one atom of that element, use the Greek prefix for that number.

2. The name of second element is

shortened and the suffix "ide" is added. If more than one atom of the second element, then use the Greek prefix for that number.Here I'm talking chemistry to a couple of textbooks authors. If I hear Greek_something_Greek_something_ide, I know they are talking about a non-metal compound of two elements even if I didn't catch the element names.

When reading chemistry, you see and hear Greek words for counting the elements in non-metal compounds, but when discussing compounds made from a metal and a non-metal, you see Roman Numerals but hearArabic numerals. It almost makes you want to use your sword on someone.

 Written: iron(II) chlorideSpoken: iron two chloride

Written: cobalt(III) oxideSpoken: cobalt three oxide

Notice that the Roman numeral (III) is spoken as if it were the Arabic numeral

"3". We say "three" not "I, I, I", which would make people think you stutter.

CrO2

Spoken: "chromium four oxide"

Written out: Chromium (IV) oxide

Another puzzler: You see the formula CrO2, but are puzzled because someone calls it "chromium four oxide". To you it looks like there's two oxygens not four. The reason for this is that the "four" is referring to the charge on the chromium not the number of oxygen atoms.

Here's a diagram of what chromium and oxygen atoms look like individually.

They start off neutral because the electrons (e-) they have match the number of protons (p+) they have. Since each oxygen has a stronger pull on electrons than does chromium, each will pull off two electrons from the chromium. Chromium has four outer electrons and these get grabbed by the two oxygen atoms. Now chromium has 4 more protons than it does electrons, so it is now 4+ charge. The oxygens have gained 2 electrons each, so

they are now 2- charge. Because these elements now have opposite charges, they stick together to make chromium (IV) oxide.

   Copper(II) chloride

> CuCl2

Calcium chloride > CaCl2

Sodium chloride > NaCl

Two more puzzlers: 1) Sometimes you hear Roman numerals used and sometimes not. 2) Why did they write two chlorines for calcium chloride (CaCl2), but only one chlorine for sodium chloride (NaCl)?

No need to say more than what's needed:

You wouldn't try to use hand signals to tell your friends here that there's aShark-with-a-lot-of-sharp-teeth right behind them. Giving them the signal for "shark" is all you need.

Chemists are like scuba divers. There's no need to say more than what's necessary. When a group shares a certain amount of knowledge, communication can be shortened because of this shared

knowledge.Chloride ion = Cl-

Sodium ion = Na+ and attracts one Cl-

Calcium ion = Ca2+ and attracts two Cl-

NaCl (no need to say one chlorine because sodium can only attract one)

CaCl2 (no need to say two chlorines, in other words, you would not say calcium dichloride because it's unnecesary when you know that

Chemistry nomenclature can be puzzling if we don't have the knowledge that chemists share. What they know is the charge on elements.

Chlorine is a negative one charge, so it's attracted to the positive metal ions like sodium and calcium. When a sodium atom becomes a charged ion, it always becomes 1+ charge. Calcium always becomes a 2+ (two plus) charge.

calcium has 2+ charge. That 2+ charge would always attract two chloride ions which have a negative one charge each).Copper ion = Cu+ or Cu2+

copper (I) chloride means Cu+ so attracts one Cl- (CuCl)

copper (II) chloride means Cu+ so attracts two Cl- (CuCl2)

Unlike copper and sodium, a copper ion can be either 1+ charge or a 2+ charge. So simply saying copper chloride doesn't tell you how many chloride ions are attached to the copper. However, if you indicate the charge on the copper, then others can figure out how many

chlorine atoms are connected.This is the Periodic Table where the middle is left out so we can focus on both ends. Notice that elements in the first column will achieve a +1 charge (also written 1+) if they lose their outer single electron. Sodium (Na) mentioned above is in this column. The second column are metals that acquire a plus two charge when they lose their two outer electrons. Calcium mentioned above is in this column. Non-metals

are on the right side and they become negatively charged as they take electrons away from the metals. Notice chlorine has a negative one charge.

MgCl2

Do not say magnesium d

ichlorideSaying magnesium chloride is

enough

It's the knowledge of the charges that speeds up communication. For example, a person does not need to say "magnesium dichloride" because magnesium is in the plus 2 charge column, and since chlorine is a negative 1 charge, there will always be two chloride ions attached to a magnesium ion.

Here's the motto: "Don't tell me something I already know."

It's like saying "yellow bananas", "wet water", or "4 legged horse." Don't use these extra words that are already common knowledge.

On the other hand, don't leave out words that are needed.The main ingredient of glass is silicon dioxide (SiO2). Sometimes aluminum oxide (Al2O3) is added to make the glass more resistant to

chemicals.

Why didn't we say dialuminum trioxide for (Al2O3)? One reason is that we have a metal combined with a non-metal, so we don't use Greek prefixes to count the atoms.

How do we know aluminum oxide has two aluminum atoms and three oxygen atoms?

We refer to this Periodic Table that lists the charges that these elements can have. Aluminum is in the +3 column meaning it loses 3 electrons to become +3 charge. Oxygen is in the -2 column and can have a -2 charge. Having opposite charges, the two are attracted to each other. However, after they are together, they still have an overall +1 charge.

(Al3+O2-)+

That means as a pair, they will attract another negative

oxygen atom.(Al3+O2-)+  ← O2-

This resulting threesome now has a negative one charge (3+ & 4-=1-), so they will now attract a positive aluminum ion. (O2-Al3+O2-)- ← Al3+

This results in a group that has a plus 2 charge(Al3+O2-Al3+O2-)2+

Being positive they now attract a O2-. (Al3+O2-Al3+O2-)2+ ← O2- Now all together there is no charge, so the compound attracts nothing else and we

end with the final compound & formula.(O2-Al3+O2-Al3+O2-)which is Al2O3. Also, aluminum never has other charges, so we can depend on it having a +3 charge, so we don't write: aluminum(III) oxide, we only write aluminum oxide.A compound that comes together just like aluminum oxide is iron(III) oxide (rust). Notice for the iron compound, I wrote "(III)". That's because iron can have either a

plus 2 charge or a plus 3 charge. So I had to specify which one. It's formula is like aluminum oxide (Al2O3); it's Fe2O3. Two iron atoms with plus 3 charge each balances with three oxygen atoms with negative 2 charge each just like the aluminum and oxygen atoms did.

Learning the language of chemistry takes time. Like any language, the more you are learn the faster it is to learn more. Also, understanding the logic behind the naming rules helps. Even though there is quite a bit of memorization in nomenclature, remember, it's not just names that are important, it's the chemical behind the name.

The payoff with learning how to speak chemistry is that it

lets you communicate with so many others around the world that also have learned the language of chemistry.