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IONIC COMPOUNDS
FORMATION OF IONS (pp 71 - 74)
1. Many of the properties of the elements are due to the valence electrons.
2. These same electrons are involved in the formation of chemical bonds between two atoms.
3. Electron dot structures help keep track of the valence electrons.
4. Remember from last unit that ionization energy refers to the energy required to remove an
electron from an atom - the lower the energy, the easier it is to remove the electron.
5. Another property, ________________________________________, refers to how much
attraction an atom has for electrons.
6. When an electron is added to an atom having high electron affinity, energy is released.
7. The nonmetals have high electron affinity, while the metals have low electron affinity.
8. This is because nonmetals want to gain electrons while metals want to lose electrons.
9. Elements gain, lose, or share valence electrons so their valence shell mimics that of a noble
gas.
10. Noble gases have a full outermost energy level (valence shell) ________________________,
which gives them a stable ______________________________.
Positive Ions
1. A positive ion forms when an atom loses one or more valence electrons.
2. The process is:
3. A positive ion is called a ______________________________.
4. Losing electrons gives the resulting cation an electron configuration similar to that of a noble
gas, but it does not change the element into a noble gas.
5. The protons that establish the character of the element remain in the nucleus.
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6. The reactivity of metals is based on the ease with which they lose valence electrons.
Group 1:
Group 2:
Group 3:
Group 13:
Group 14:
7. Transition elements lose electrons from both the _____ and _____ orbitals. This gives them a
wide variety of positively charged cations.
Negative Ions
1. A negative ion forms when an atom gains one or more electrons.
2. The process is:
3. Nonmetals have a great attraction for electrons and form a stable octet by gaining electrons.
4. A negative ion is called an _________________________.
5. Nonmetals form anions as follows:
Group 14:
Group 15:
Group 16:
Group 17:
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IONIC BONDS (pp 75 - 78)
1. Oppositely charged ions attract one another.
2. The electrostatic forces that hold oppositely charged particles together in a compound are
called an ________________________________________.
3. Any compound formed in this manner is called an __________________________________.
4. Ionic compounds have no resultant charge – they are neutral.
5. The process for sodium chloride looks like:
Properties of Ionic Compounds
1. The chemical bonds that occur between the atoms in a compound determine many of the physical and
chemical properties of the compound.
2. In an ionic compound, the positive and negative ions are packed into a regular repeating pattern that
balances the forces of attraction and repulsion.
3. This particle packing forms an ionic crystal lattice.
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4. The three-dimensional crystal lattice gives the crystal its shape and properties.
5. Ionic compounds are: very strong, rigid, have high melting and boiling pints, and require a
large amount of energy to be broken.
NAMES AND FORMULAS FOR IONIC COMPOUNDS (pp 85 - 94)
1. Since the generic term “salt” can mean any one of thousands of chemical compounds, a better
system is needed to describe an ionic compound.
2. The system is based on the chemical symbols on the periodic table and was developed by a
German chemist in 1919 named Alfred Stock.
Monatomic Ions
1. A monatomic ion is either a cation or an anion formed from a single atom.
2. To write the chemical symbol for a monatomic ion you must indicate both the symbol for the
element and its charge.
***** Write the symbol for the ions formed from:
Cesium
Fluorine
Beryllium
Oxygen
Aluminum
3. The charge of a monatomic ion is also called its ______________________________, or
___________________________________.
4. Groups 1, 2, 3, 13-18 generally have one oxidation number while the transition elements
typically have more than one.
5. Some elements have both positive and negative oxidation numbers. The oxidation state used
will depend on the other elements bonding with it.
6. The oxidation number, or oxidation state, of an element in an ionic compound equals the
number of electrons transferred from one atom and accepted by the other atom.
7. The nomenclature for monatomic ions is fairly simple.
8. A monatomic cation is named using the element’s name followed by the word __________.
The word ion must be included in the name of the ion in order for it to be correct.
Na+
Al3+
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9. A monatomic anion is named by dropping the ending of the element’s name and adding the
suffix _______________, followed by the word __________.
Cl-
O2-
N3-
***** Name the following ions:
H+
H-
O2-
S2-
Ca2+
F-
Li+
Ba2+
I-
P3-
Nomenclature for Ions with Multiple Charges
1. The transition elements form many different cations depending upon the number of electrons
given up.
2. To distinguish between the various charges, Roman numerals are used to represent the number
of electrons given up – in other words – the charge.
3. Roman numerals are used _______________ when naming cations that have
___________________________________ positive charge from which to choose.
4. To do otherwise is ___________________.
5. Anions, even though they may have more than one negative charge, __________ use Roman
numerals.
6. The naming process is:
(a)
(b)
(c)
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*****Name the following ions
Fe2+
Mo7+
Cr3+
Zn2+
V5+
Writing Formulas for Ionic Compounds
1. An ionic compound is _______________ even though it is composed of charged ions.
2. Steps for writing a chemical formula:
barium sulfide
molybdenum (V) oxide
a. List the symbol for the cation and its charge.
b. List the symbol for the anion and its charge.
c. Write the symbols for the ions, side-by-side, with the cation first.
d. If the charges don’t balance, criss-cross them.
e. The charge number – no sign – becomes the subscript for the cation or anion.
3. Chemical formulas must reflect the actual composition of the compound.
***** Determine the formulas for the following compounds:
aluminum nitride
aluminum oxide
strontium phosphide
iron(II) oxide
calcium chloride
tin(IV) fluoride
rubidium iodide
copper(II) arsenide
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Naming Ionic Compounds
1. Ionic compounds consisting of two ions, cation and anion, are known as
______________________________.
2. To name a binary compound:
(a)
(b)
(c)
3. Cations with variable oxidation states:
Cu: +1, +2
Ti: +2, +3, +4
Au: +1, +3
Cr: +2, +3, +6
Co: +2, +3
Mn: +2, +3, +4, +7
Fe: +2, +3
Ni: +2, +3
Pb: +2, +4
Pt: +2, +4
Sn: +2, +4
4. Name: Rb2Se
5. Name: Pb3N4
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***** Name the following ionic compounds:
MgBr2
MnCl4
Al2S3
VI3
Ni2O3
YN
BeO
CrO3
Polyatomic Ions
1. A ______________________________ is an ion made of two or more atoms bonded together
that function as a single ion.
2. Polyatomic ions have special names that must be memorized.
3. Polyatomic ions can be either cations or anions.
4. Ionic compounds formed by polyatomic ions must be neutral.
5. Polyatomic ions have charges just like the monatomic ions. The charge sign is written to the
right of the ion’s formula. Remember that this charge applies to the _______________ ion, not to
any individual element.
6. Parentheses are used to group polyatomic ions. The subscript outside the parentheses refers to
everything within the parentheses.
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Polyatomic Ion List
Memorize the following polyatomic ion names and symbols, including the charges.
NH4+
ammonium ion
OH-
hydroxide ion
NO2-
nitrite ion
PO43-
phosphate ion
NO3-
nitrate ion
ClO-
hypochlorite ion
SO32-
sulfite ion
ClO2-
chlorite ion
SO42-
sulfate ion
ClO3-
chlorate ion
CO32-
carbonate ion
ClO4-
perchlorate ion
HCO3- bicarbonate ion
CrO42- chromate ion
C2H3O2- acetate ion
MnO4- permanganate ion
CN-
O22-
cyanide ion
peroxide ion
Compounds With Polyatomic Ions
1. Ionic compounds containing polyatomic ions are named in the same manner as binary ionic
compounds. The cation is listed first, followed by the anion.
2. Formulas for ionic compounds containing polyatomic ions are written in the same manner as
binary ionic compounds. The cation formula is written first and the anion formula is written
second.
3. Special notes for formula writing:
(a) When more than one polyatomic ion is used in a formula, enclose it inside a set of parentheses
and then add a subscript outside the parentheses.
Ex:
(b) Parentheses are ____________________ to be used if only one polyatomic ion is used in the
formula.
***** Write the formula for strontium perchlorate.
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***** Write the formula for the following compounds:
aluminum sulfate
hydrogen peroxide
magnesium hydroxide
sodium bicarbonate
copper (II) acetate
ammonium hydroxide
copper (I) phosphate
***** Name the following compounds:
NaNO3
Fe(OH)3
(NH4)2SO4
Cu3(PO4)2