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Chapter 5
The Periodic Table
5-1 Organizing the
Elements
• What does the word “periodic” mean?
• Periodic: recurring at _______ intervals
• Periodic table – is an ___________ of
elements in__________ based on a set of
properties that repeat from _________
to row
Mendeleev 1869
• See Figure 3 on page 127
• Arranged elements according to increasing
_____________ in rows
• Put elements of similar properties in the
same __________
• Left blank spots in table which predicted
_________ of elements not yet
discovered
Evidence Supporting
Mendeleev’s Table
• Named eka-aluminum to the element that
belonged one space ________ aluminum on
the table
• 1875- French chemist discovered a new
element and named it ________ (Ga)
• Gallium is a soft metal used in ________
signals
Similarity of the two
• Eka-aluminum and Gallium were similar in
properties, so they were determined to be
the ________
• The close match between Mendeleev’s
_________ and the actual properties of
new elements showed how ________ his
periodic table could be
Questions
1. Which of the following is a symbol
for an element?
a. Aluminum
b. Al
c. al
d. AL
Questions
2. Is flammability a physical property
or a chemical property?
Questions
3. What happens to the composition of
matter during a physical change?
Does it change or remain the same?
Questions
4. What does the atomic number of an
element represent?
Question
5. Isotopes of element have different
numbers of
a. Neutrons
b. Electrons
c. Protons
d. nuclei
Question
6. True or False : Electrons in atoms
occupy orbitals in energy levels
5-2 The Modern Periodic
Table
• _____________ developed the
periodic table before the discovery
of___________.
• In the modern periodic table,
elements are arranged by increasing
_____________
Periods
• Each_______ in the table of elements is called a
__________
• Period 1 has ________ elements
• Periods 2 and 3 have ________ elements
• Periods 4 and 5 have ___________elements
• Period 6 has ________elements
• There are ________ periods total on the
periodic table
• The number of _____________ per period varies
because of the number of available orbitals
increases from energy level to energy level
Groups
• Each _________ on the periodic table is called a
__________
• The elements within a group have similar
_________
• Properties of elements__________ in a
predicable way when atomic number are used to
arrange elements into groups
• The pattern of repeating properties is the
_________
• There are ________ groups on the periodic table
Atomic Mass
• _____________ is a value that
depends on the distribution of an
element’s isotopes in nature and the
masses of those isotopes
• An atomic mass unit________ is
defined as one twelfth the mass of
carbon-12 atom
Average Atomic Mass
• Weighted __________ of
the atomic masses of the
naturally occurring
isotopes of an element
What is the aver. atomic
mass of the chlorine?
Isotope
Isotope Mass
(amu)
% Abundance
Chlorine-35 34.96885
75.771
Chlorine-37 36.96590
24.229
Weighted Averages
• Average Atomic Mass =
•
(isotope mass)(relative abundance[dec]) + (isotope mass)(relative abundance[dec])
• (0.75771)(34.96885amu) + (0.24229)(36.96590amu)
• = ___________
ISOTOPES
• Atoms of the _____________ that
differ in __________
• Have the same # protons but
different # neutrons
Classes of Elements
•
Elements are classified as_______, ___________, and
__________
•
Metal:
– Good conductor of heat & electricity
– ____________ –able to be drawn into a fine wire
– Malleability – can be hammered or rolled into thin____________
•
Nonmetal
– Poor conductor of heat & electricity
– _____________
•
Metalloids
– Some characteristics of ____________ & _______________
Transition Metals
• ________________ are elements
that form a bridge between the
elements on the left and right sides
of the table
The Lanthanides
• The ___________ elements with
atomic numbers from 58(cerium, Ce)
to 71(lutetium, Lr)
• Similar in chemical and physical
properties
The Actinides
• The ________________ elements
with atomic number from 90(thorium,
Th) to 103(lawrencium, Lr)
Variation across a period
• Across a period from left to right, the
elements become ________ metallic and
more nonmetallic in their properties
• Most __________ metals are on the left
side of the table
• Most reactive________ are on the right
in Group 17
5-3 Representative
Groups
• __________ electron – is an electron that
is in the ________ occupied energy level
of an atom
• Elements in a _______ have similar
properties because they have the
_______ number of valence electrons
• Valence electrons explain the location of
_______, hydrogen has a ______
electron
Alkali Metals
• Elements in Group ______ are called
______ metals.
• ________ valence electron and are
extremely _________
• The reactivity of alkali metals
___________ from the top of Group
1A to the bottom
The Alkaline Earth
Metals
•
The elements in Group _______ are called
_____________metals
•
All alkaline earth metals have ___________ valence electrons
•
They are ________ than group 1A
•
Differences in reactivity among the alkaline earth metals are
shown by the ways they react with _________
•
Calcium, strontium and barium react easily with _______ water
•
Magnesium will react with________water. No change appears to
occur when beryllium is added to water
The Boron Family
• Group ________ contains the
metalloid ________.
• ___________ is the most abundant
metal in the Earth’s crust
• ________that contains boron is
used to make laboratory glassware
such as flasks
The Carbon Family
•
•
•
•
Group _______ contains nonmetal carbon
Two ________ – silicon and germanium
Two metals – lead and ________
Except for _______, most of the
compounds in your body contains carbon
• __________ is the second most abundant
element in the Earth’s crust
The Nitrogen Family
• Group ______ contains two
nonmetals – nitrogen and phosphorus
• _____ metalloids – arsenic and
antimony
• One metal –bismuth
• Besides nitrogen, ___________
often contain phosphorus
The Oxygen Family
• Group _______ has three nonmetals
– oxygen, sulfur, and selenium
• Two metalloids – tellurium and
polonium
• All have_______valence electrons
• ___________ is the most abundant
element in the Earth’s crust
The Halogens
• The elements in Group _______ are called
halogens
• They have ________ valence electrons
• Despite their physical differences, the
halogens have ________ chemical
properties
• They are highly reactive ___________
• _________ is the most reactive
The Noble Gases
• The elements in Group_______ are called
the noble gases
• Helium has _______ valence electrons
• All other noble gases have ______ valence
electrons
• The noble gases are________
and________ and extremely_________
• All the noble gases except ______ are
used in “neon” lights