Nomenclature worksheets.pdf

Monatomic Ions

Ions are atoms that have either lost or gained electrons. While atoms are neutral, ions are
charged particles.
Ø A loss of electrons results in a positive ion or cation (pronounced “cat-eye-on”).
Ø A gain of electrons results in a negative ion or anion (pronounced “an-eye-on”).
Although ions and elements have similar chemical symbols, they are entirely different
substances with different physical properties.
A. Monatomic Ions
In order to determine the charge of monatomic ions, you can use the periodic table as a guide: Ion Charge
Examples
(Column)
These elements lose one electron to form +1 ions.
These elements lose two electrons to form +2 ions.
The elements in groups 3-12 are called transition metals. These elements always lose electrons to form positive ions (cations) but their charges vary.
For example, iron can form a +2 or a +3 ion. In cases like these, you must be told which ion to use. These elements lose three electrons to form +3 ion.
The charges on these ions vary. Carbon and silicon do not form ions. For the rest of the group, you must These elements gain three electrons and form –3
These elements gain two electrons to form –2 ions.
These elements gain one electron to form –1 ions.
These atoms do NOT form ions. Their charge is always zero.
Simple cations are named by saying the element and adding the word “ion.”
Na+ is called “sodium ion”
Mg2+ is called “magnesium ion”
Simple anions are named by dropping the ending off the element name and adding “ide.”
F- is called “fluoride”
O2- is called “oxide”
N3- is called “nitride”
Note: the charge of a monatomic anion is equal to the group number minus 18.
Monatomic Ions
Use a periodic table to complete the table below: Element Name
Element Symbol
Simple Binary Ionic Compounds
Ionic compounds are compounds formed by the combination of a cation and a anion.
(Think: “metal plus nonmetal”). Ionic compounds are more commonly known as
“salts.” Binary ionic compounds are compounds containing only two elements, as
demonstrated in the examples below.
When writing formulas for ionic compounds, we use subscripts to indicate how many of
each atom is contained in the compound. Remember that even though ions have
charges, ionic compounds must be neutral. Therefore, the charges on the cation and
the anion must cancel each other out. In other words, the net charge of an ionic
compound equals zero.

Example 1:
For a salt containing sodium ion, Na+, and chloride, Cl-, the ratio is one to one. The
positive charge on the sodium ion cancels out the negative charge on the chloride.
(+1) + (-1) = 0
Therefore, the formula for the salt is NaCl. (The actual formula is Na1Cl1, but chemists
omit subscripts of 1).

Example 2:
For a salt containing calcium ion, Ca2+, and chloride, Cl-, the ratio can’t be one to one.
(+2) + (-1) = +1
Remember that ionic compounds must be neutral. In order to yield a neutral compound,
two chlorides must bond to the calcium ion:
(+2) + 2(-1) = 0
So, the formula for this salt is CaCl2.

Nomenclature:
When naming ionic compounds, simply write the element name of the metal followed by
the ion name of the nonmetal. (Remember: the metal ion (cation) is always written
first!)
NaCl is called “sodium chloride,” and CaCl2 is called “calcium chloride.”
Simple Binary Ionic Compounds
Please complete the following table: Polyatomic Ions

Polyatomic ions contain two or more different atoms (polyatomic means “many atoms”).
Here are some common e xamples:
a. ammonium ion, NH +
4 (the only positive polyatomic ion you need to know)

b. “ATE” ions: contain an atom bonded to several oxygen atoms:

c. “ITE” ions: remove one oxygen from the “ATE” ion and keep the same charge:
Nitrite = NO -

d. Other common complex ions:
Hydroxide = OH-

Ionic Compounds Containing Polyatomic Ions

As you’ve already learned, ionic compounds are formed by the combination of a
positive ion (cation) and a negative ion (anion). This is the same when dealing simple
ions or complex ions. Be careful to note, however, that complex ions are grouped
together and should not be separated. In other words, don’t ever separate the sulfate
ion, SO 2-
4 into sulfur and oxygen. If it’s written as a group, keep it as a group!

Since complex ions come in groups, things can get tricky when using subscripts. As a
result, we use parentheses to separate the ion from the subscript:
If we need two sulfates in a compound, we write: (SO4)2.
If we need three nitrates in a compound, we write: (NO3)3.
And, just as before, the net charge of the compound must be zero. For a salt
containing sodium ion, Na+, and nitrate, NO -
3 , the ratio would be 1:1 since the positive and negative charges cancel out. Therefore, the formula is NaNO3 and is called sodium nitrate. (Note: no parentheses are necessary here). For a salt containing calcium ion, Ca2+, and nitrate, NO - calcium ion for every two nitrates). So, the formula would be Ca(NO3)2.
Ionic Compounds Containing Polyatomic Ions
Please complete the following table: Name of Ionic Compound
Formula of Ionic Compound
Ionic Compounds Containing Transition Metals
The transition metals are the elements located in the middle of the periodic table (in groups 3-
12. Unlike the group 1A and 2A metal ions, the charges of transition metal ions are not easily
determined by their location on the periodic table. Many of them have more than one charge
(also known as an oxidation state). There are eight transition metals that you should highlight
on your periodic table:
Each of these elements form more than one ion and therefore must be labeled accordingly.
For example, iron forms two ions: Fe2+ and Fe3+. We call these ions “iron (II) ion” and “iron (III)
ion” respectively. (See “Table of Transition Metal Ions”).
When naming any ion from the elements listed above, you MUST include a Roman numeral in
parentheses following the name of the ion. The this roman numeral is equal to the charge on
the ion. We don’t include the “+” because all metal ions are positive. Here are two more
examples:
Similarly, when naming a compound containing one of these transition metals, you must
include the Roman numeral as well. “Iron Chloride” isn’t specific enough since the compound
could contain either iron (II) or iron (III) ion. You must specify the charge on the iron.
Iron (II) chloride contains the Fe2+ ion. When combined with chloride, Cl-, we know the formula
must be FeCl2.
Iron (III) chloride contains the Fe3+ ion. This time, three chlorides are required to form a neutral
compound. Therefore, the formula is FeCl3.
By looking at the formula of an ionic compound, we can determine the charge (oxidation
state) of the metal.
Example: Write the name of Co2O3
1. Recognize that Co, cobalt, is a transition metal. This means that you must include a Roman
numeral after its name. So, the basic name will be Cobalt (__) Oxide. 2. To find the charge on cobalt, use oxide as a key. Oxide has a charge of –2 so three oxides 3. What balances a –6 charge? A +6 charge! So, the positive half of the compound must 4. Since there are two cobalt ions, the charge is split between them. So, each one has a +3 charge. Therefore, we are using the Co3+ ion and the compound is called cobalt (III) oxide.

Remember that anions (negative ions) always have a definite charge. When dealing with
compounds containing transition metals, look to the anion first. Determine the charge of the
anion and then solve to figure out the charge of the cation.
When dealing with metals other than the transition metals, you don’t need Roman numerals. In
other words, calcium ion, Ca2+ is always +2. Don’t call CaCl2 “calcium (II) chloride.” Its name is
“calcium chloride.”
Ionic Compounds Containing Transition Metals
Please complete the following table: Name of Ionic Compound
Formula of Ionic Compound
Ionic Compounds Summary
Naming Binary Covalent Compounds
Binary covalent compounds come from the combination of two nonmetals (or a nonmetal and a metalloid). These compounds do not involve ions; as a result, they have a slightly different naming system. Chemists use prefixes to indicate the number of atoms in each compound. The prefixes are listed in the table below: # of Atoms
When naming binary covalent compounds, the first element name is given followed by the second element with an “ide” ending. The first element gets a prefix when there is more than one atom in the compound.* The second element ALWAYS gets a prefix. Here are some examples: Compound
* Notice that the prefix “mono” is omitted in these cases Prefixes are necessary when naming covalent compounds because the atoms can combine in any whole number ratio. N2O, for example, cannot simply be called “nitrogen oxide,” because there are several other compounds that contain nitrogen and oxygen. We must specify that there are two nitrogen atoms bonded to a single oxygen atom. When dealing with ionic compounds, there is only one way for a cation and a nion to combine to form a neutral compound. As a result, there is no need to use prefixes. This is why CaCl2 is called “calcium chloride,” rather than “calcium dichloride.” Binary Covalent Compounds
Please complete the following table: Name of Covalent Compound
Formula of Covalent Compound

Determine whether the following compounds are covalent or ionic and give them their
proper names.
1. Ba(NO3)2
2. CO
3. PCl3
4. KI
5. CF4
6. MgO
7. Cu2S
8. SO2
9. NCl3
10. XeF6
Shortcut for Formula Determination:
Use the following method when asked to determine the formula of an ionic compound: 1. Write the two ions with their charges (metal first). 2. Ignoring the + or – charges, “crisscross” the numbers and make them subscripts. 3. Then, rewrite the formula, dropping the charges.
Example 1:
Write the formula for calcium chloride:
1. Write the two ions with their charges (metal first). 2. Ignoring the + or – charges, “crisscross” the numbers and make them subscripts:
3. Then, rewrite the formula, dropping the charges. In this case, the formula is: CaCl2.

Example 2:
Write the formula for magnesium oxide:

1. Write the two ions with their charges (metal first). 2. Ignoring the + or – charges, “crisscross” the numbers and make them subscripts: 3. Then, rewrite the formula, dropping the charges. The rewritten formula is: Mg2O2. Note: Since the subscripts for the anion and cation are the same, the formula reduces to
Mg1O1.
Therefore, the correct formula is written as: MgO.

Source: http://killarneyschool.ca/mrsprott/Grade%2010/Chemistry/Nomenclature_Worksheets%20covers%20all.pdf