Lecture #6
The Periodic Table
and
Naming Simple Compounds
Chemistry 142 A
James B. Callis, Instructor
Winter Quarter, 2006
Classification of the Elements
• Most of the elements are metals - metallic
luster, ability to conduct electricity and heat,
and malleability.
• The remaining elements are classified as
nonmetals - no luster, poor conductors of
electricity and heat and brittleness.
Sub-Classes of Metals
• Alkali metals - (lithium, sodium, potassium,
rubidium and cesium) - soft, low melting points,
react with water to liberate hydrogen, form 1:1
compounds with chlorine.
• Alkaline earths - (beryllium, magnesium, calcium,
strontium, barium and radium) - react in a 1:2 ratio
with chlorine.
• Transition metals - (e.g. iron, copper, silver, gold,
tungsten and cobalt) - structural metals
• Metalloids - (antimony, arsenic, boron, silicon and
tellurium) - intermediate between metals and
nonmetals.
Non-Metals
• Chalcogens - (oxygen, sulfur, selenium and
tellurium) - form 1:1 compounds with
alkaline-earths, but 2:1 compounds with
alkali-metals.
• Halogens - (fluorine, chlorine, bromine and
iodine) - highly reactive and form 1:1
compounds with alkali-metals.
• Noble gases - (helium, neon, argon,
krypton, radon) - virtually inert to chemical
reactions.
Periodic Variation
• When the properties of the elements are
plotted against atomic number, we observe a
periodic variation in their properties.
• The boundaries of the periods seem to be
marked by the appearance of the noble gases at
2, 10, 18, 36, 54 and 86 amu.
• The variations in both melting point and
atomic radius seem to correlate (inversely).
• The different element classifications also
appear cyclically in this periodic variation.
Variation of Atomic Radius with Atomic
Number
Atomic Radius, A
3
2.5
2
1.5
1
0.5
0
0
10
20
30
40
50
60
Atomic Number
70
80
90
100
Periodic Variation in Properties
Atomic Number
0
1
10
20
30
Boiling Point K
40
50
60
70
80
90
100
3
Atomic radius (Å)
2.5
2
100
1.5
1
1000
0.5
10000
0
Atomic Radius, A
Boiling Point, K
10
The Periodic Table
• A two dimensional classification scheme for the
elements. The columns or groups arrange the elements
by chemical classification, as discussed above. The
chemical variation across the rows or periods reflect the
cyclic variation exhibited in the graphs above.
• The periodic table is not only an organizing principle,
but it has (had) predictive power as well.
• As valuable as the periodic table is, the explanation of
its organization was not obvious. It was not until the
advent of quantum mechanics that the electronic
structure of the atoms could be used to explain the
periodic variation in properties.
Groups in the Periodic Table
Main Group Elements (Vertical Groups)
Group IA - Alkali Metals
Group IIA - Alkaline Earth Metals
Group IIIA - Boron Family
Group IVA - Carbon Family
Group VA - Nitrogen Family
Group VIA - Oxygen Family (Calcogens)
Group VIIA - Halogens
Group VIIIA - Noble Gases
Other Groups ( Vertical and Horizontal Groups)
Group IB - 8B - Transition Metals
Period 6 Group - Lanthanides (Rare Earth Elements)
Period 7 Group - Actinides
The Periodic Table of the Elements
H
Li Be
Na Mg
B C N
Al Si P
He
O F Ne
S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr NbMo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Du Sg Bo HaMe
Ce Pr Nd PmSm Eu Gd Tb Dy Ho Er TmYb Lu
Th Pa U Np PuAmCmBk Cf Es FmMd No Lr
The Alkali Metals
The Halogens
The Alkaline
Earth Metals
The Noble Gases
The Periodic Table of the Elements
H
Li Be
NaMg
He
B C N O F Ne
Al Si P S Cl Ar
K Ca Sc Ti V CrMn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Du Sg Bo Ha Me
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Th Pa U Np PuAmCm Bk Cf Es FmMd No Lr
Boron family
Nitrogen family
Carbon Family
Oxygen Family
The Periodic Table of the Elements
H
Li Be
Na Mg
B C N
Al Si P
He
O F Ne
S Cl Ar
K Ca Sc Ti V CrMn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr NbMo Tc Ru Rh PdAg Cd In Sn Sb Te I Xe
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Rf Du Sg Bo Ha Me
The Transition Metals
Ce Pr Nd PmSm Eu Gd Tb DyHo Er TmYb Lu
Th Pa U Np PuAmCmBk Cf Es FmMd No Lr
Lanthanides: The
Rare Earth Elements
The Actinides
Naming Binary Compounds
(Type I; Ionic)
• The cation is always named first and the anion
second.
• A monatomic cation takes its name from the name
of the element, e.g. Na+ is called sodium in the
names of compounds containing this ion.
• A monatomic anion is named by taking the first
part of the element and adding –ide, e.g. Cl- is
chloride.
Type I
Problem 6-1: Give the Name and Chemical Formulas of the
Compounds formed from the following pairs
of Elements
a) sodium and oxygen
Na2O
sodium oxide
CaF2
calcium fluoride
b) zinc and chlorine
c) calcium and fluorine
d) strontium and nitrogen
e) hydrogen and iodine
f) scandium and sulfur
HI
hydrogen iodide
Naming Binary Compounds
(Type II; Ionic)
• Applies to cations that can take on alternate
charge states
• Using the principle of charge balance
determine the cation charge.
• Include in the cation name a Roman
numeral indicating the charge.
Type II
Determining Names and Formulas of Ionic Compounds
of Elements That Form More Than One Ion.
Problem 6-2: Give the systematic names for the formulas
or the formulas for the names of the following compounds.
a) iron (III) sulfide - Fe is 3+, and S is 2- therefore the compound is:
Fe2S3
b) CoF2 -
c) stannic oxide - Stannic is the common name for tin (IV), Sn4+, the
oxide ion is O2-, therefore the formula of the compound is:
SnO2
d) NiCl3 -
Ionic Compounds with
Polyatomic Ions
• Polyatomic ions are assigned special names
that must be memorized.
• Special rules apply to anions that contain an
atom of a given element and different
numbers of oxygen atoms. These anions are
called oxyanions.
Start learning these boldface ones.
Rules for Families of Oxoanions
Families with Two Oxoanions
The ion with more O atoms takes the nonmetal root and the
suffix “-ate”.
The ion with fewer O atoms takes the nonmetal root and the
suffix “-ite”.
Families with Four Oxoanions (usually a Halogen)
The ion with most O atoms has the prefix “per-”, the nonmetal
root and the suffix “-ate”.
The ion with one less O atom has just the suffix “-ate”.
The ion with two less O atoms has the just the suffix “-ite”.
The ion with three less O atoms has the prefix “hypo-” and the
suffix “-ite”.
NAMING OXOANIONS - EXAMPLES
per
hypo
Root
Suffixes
“
”
ate
“
”
ate
“
”
ite
“
”
ite
Chlorine
Bromine
Iodine
perchlorate perbromate periodate
[ ClO4-]
[ BrO4-]
[ IO4-]
No. of O atoms
Prefixes
chlorate
[ ClO3-]
bromate
[BrO3-]
iodate
[ IO3-]
chlorite
[ ClO2-]
bromite
[ BrO2-]
iodite
[ IO2-]
hypochlorite hypobromite hypoiodite
[ ClO -]
[ BrO -]
[ IO -]
Binary Compounds
(Type III; Covalent –
Contain Two Nonmetals
• The first element in the formula is named first,
using the full element name.
• The second element is named as if it were an
anion.
• Prefixes are used to denote the numbers of atoms
present.
• The prefix mono- is never used for naming the
first element, e.g. CO is carbon monoxide.
Examples of Names and Formulas of
Oxoanions and Their Compounds - I
• KNO2
BaSO3 barium sulfite
• Mg(NO3)2 magnesium nitrate
Na2SO4
• LiClO4 lithium perchlorate
Ca(BrO)2 calcium hypobromite
• NaClO3
Al(IO2)3 aluminum iodite
• RbClO2 rubidium chlorite
• CsClO
KBrO3
LiIO4 lithium periodate
Examples of Names and Formulas of
Oxoanions and their Compounds - II
• calcium nitrate
• strontium sulfate SrSO4
ammonium sulfite
lithium nitrite
• potassium hypochlorite KClO
lithium perbromate
• rubidium chlorate
calcium iodite
• ammonium chlorite NH4ClO2
• sodium perchlorate
(NH4)2SO3
LiBrO4
Ca(IO2)2
boron bromate
magnesium hypoiodite Mg(IO)2
Problem 6-3: Determining Names and Formulas
of Ionic Compounds Containing Polyatomic Ions
a) magnesium perchlorate
b) (NH4)2SO3
c) calcium nitrate
Naming Acids
1) Binary acids solutions form when certain gaseous compounds
dissolve in water. For example, when gaseous hydrogen chloride
(HCl) dissolves in water, it forms a solution called hydrochloric acid.
Prefix hydro- + anion nonmetal root + suffix -ic + the word acid
hydrochloric acid
2) Oxoacid names are similar to those of the oxoanions,
except for two suffix changes:
Anion “-ate” suffix becomes an “-ic” suffix in the acid. Anion “-ite”
suffix becomes an “-ous” suffix in the acid.
The oxoanion prefixes “hypo-” and “per-” are retained. Thus, BrO4is perbromate, and HBrO4 is perbromic acid; IO2- is iodite, and
HIO2 is iodous acid.
Determining Names and Formulas of
Anions and Acids
Problem 6-4: Name the following anions and give the names and
a) I -
formulas of the acid solutions derived from them:
b) BrO3c) SO3 2- d) NO3e) CN -
Solution:
a) The anion is
b) The anion is bromate; and the acid is bromic acid, HBrO3
c) The anion is
d) The anion is nitrate; and the acid is nitric acid, HNO3
e) The anion is
Names and Formulas of Binary Covalent
Compounds
1) The element with the lower group number in the periodic table is
the first word in the name; the element with the higher group number
is the second word. (Important exception: When the compound
contains oxygen and a halogen, the halogen is named first.)
2) If both elements are in the same group, the one with the higher
period number is named first.
3) The second element is named with its root and the suffix “-ide.”
4) Covalent compounds have Greek numerical prefixes to
indicate the number of atoms of each element in the compound. The
first word has a prefix only when more than one atom of the element
is present; the second word always has a numerical prefix.
Determining Names and Formulas of Binary
Covalent Compounds
Problem 6-5: What are the name or chemical formulas of the
following chemical compounds:
a) carbon dioxide b) PCl3 c) Give the name and chemical formula
of the compound formed from two P atoms and five O atoms.
Solution:
a) carbon dioxide
b) PCl3
c) The compound formed from two P atoms and five O atoms
Answers to Problems in Lecture #6
1. (b) ZnCl2 , Zinc Chloride; (d) Sr3N2 , Strontium Nitride;
(f) Sc2S3 , Scandium Sulfide
2. (b) Cobalt (II) Fluoride; (d) Nickel (III) Chloride
3. (a) Mg( ClO4)2 ; (b) Ammonium Sulfite; (c) Ca(NO3)2
4. (a) iodide, hydroiodic acid, HI; (c) sulfite, sulfurous acid,
H2SO3 (e) cyanide, hydrocyanic acid, HCN
5. (a) CO2 ; (b) phosphorous trichloride; (c) diphosphorous
pentaoxide