The
Periodic Table
Chapter 5
Pg. 126-147
Organizing the
Elements
Chapter 5 Section 1
Pg. 126-129
The Search for Order
• Until 1750, only 17
• 1789, French chemist
elements had been
_______- grouped the
identified- mainly
known elements into
_____
categories: metals,
nonmetals, gases, and
• As the number of
earths
known elements grew,
so did the need to
_____ them into
groups based on their
________.
• 1860 (Russian chemist
and teacher) ________
was looking for the best
way to organize the
information of __ known
elements
• Found a way to approach
the problem while playing
a version of ______ (card
game)
• Made a “_________” of the elements: each
card had the element’s name, mass, and
properties
• Also paid attention to how each element
behaved in ________ with oxygen and
hydrogen
• When he lined up the cards in order of
_______ mass, a pattern emerged
• Mendeleev’s Proposal
– Mendeleev arranged the elements into ____ in
order of increasing mass so that elements with
_____ properties were in the same column.
– _____ arrangement: columns were organized by
properties instead of suits
– Within column: the masses ______ from top to
bottom
– ___________- an arrangement of elements in
columns, based on a set of properties that repeat
from row to row
• Could not make a complete table of the
elements because many elements had not yet
been ________.
• Mendeleev left _____ in his table for the
missing elements, he was confident that the
gaps in his table would be filled by new
elements
• He used ________ of elements located near
the blank spaces in his table to _____
properties for undiscovered elements
• Mendeleev was ___ the first to arrange
elements in a periodic table or leave spaces in
the table for missing elements
• Mendeleev was the f____ to offer the best
explanation for how the properties of an
element were related to its ______ in the
table
• The placement of elements on the table
reveals the link between the atomic ________
of elements and their properties
• Mendeleev _____ missing elements
– Ex: eka-aluminum (belonged one space below
aluminum on the table) He predicted that ekaaluminum would be a soft metal with a low
melting point and a density of 5.9 g/cm3
• 1875- French chemist discovered a new
element- named it _______ (Ga) in honor of
______
– Gallium is a soft metal with a melting point of
29.7°C and a density of 5.91 g/cm3
• The close _____ between Mendeleev’s
predictions and the actual properties of new
elements showed how ______ his periodic
table could be
Chapter 5 Section 2
Pg. 130-138
The Modern Periodic Table
• Piano keys are in ______ (the interval
between any two notes with the same name)
– octa- means eight
• Because the scale _______ at regular eightnote intervals, the scale is an example of a
periodic pattern
• The sounds of musical notes that are
separated by an octave are related, but they
are not ________- similar to elements in
columns
• Mendeleev developed his periodic
table ______ the discovery of
______
• In the modern periodic table,
elements are arranged by _______
atomic number (number of protons)
• Periods
–Each row is a _______
–The number of elements per
period varies because the number
of available _____ increases from
energy level to energy level
The Periodic Law
• Groups
– Each ______ is a group
– The elements within a group have ______
properties
– Properties of elements repeat in a __________
way when atomic numbers are used to arrange
elements into groups
– Members of a group have similar chemical
properties
– Periodic ____- the pattern of repeating properties
The Periodic Law
• Atomic mass is a value that depends on the
distribution of an element’s ______ in nature
and the masses of those isotopes
• Atomic Mass Units
– The mass of an atom in grams is extremely ____
and not very useful because the samples of matter
that scientists work with contain ______ of atoms
– To have a convenient way to compare the masses
of atoms, scientists chose one isotope to serve as
a _______
– An atomic mass unit (amu) is defined as one
twelfth the mass of a carbon-12 atom
• Isotopes of Chlorine
– Most elements exist as a _____ of two or more
isotopes
– There are two ______ isotopes of chlorine,
chlorine-35 and chlorine-37
– An atom of chlorine-35 has 17 protons and 18
neutrons
– An atom of chlorine-37 has 17 protons and 20
neutrons
• Weighted Averages
– The isotope that occurs in _____ about 75% of the
time (chlorine-35) contributes three times as
much to the ______ as the isotope that occurs in
nature about 25% of the time (chlorine-37)
• First- elements are classified as solids, liquids,
or gases, based on their _____ at room
temperature
• Black: solids
• Purple: liquids
• Red: gases
• Second- elements are divided into those that
occur ________ and those that do not
– All but 2 elements (1-92) occur on ____
– Elements 93 and higher do not occur naturally
(white)
• Third- classification system puts elements into
_______ based on their general _______;
elements are classified as metals, nonmetals,
and metalloids
– Metals: on left
– Nonmetals: on right
– Metalloids: in between
• Metals
– _______ of the elements (blue boxes)
– Good conductors of electric current and heat
– ______ at room temperature (except mercury)
– Most are malleable
– Many are ________ (can be drawn into thin wires)
– Some are extremely reactive and some do not
react easily
• Metals continued…
– __________ metals: metals in groups 3 through
12; form a _______ between the elements on the
left and right sides of the table
• one property of many transition metals is their ability
to form compounds with distinctive colors
• Nonmetals
– Elements that are _____ conductors of heat and
electric current
– Low boiling points
– Many are ______ at room temperature
– Those that are solid at room temperature tend to
be ______
– _______ is the most reactive nonmetal
• Metalloids
– Elements with properties that fall ________ those
of metals and nonmetals
– Ability to conduct electric current varies with
__________
• Si and Ge good insulators at low temperatures and
good conductors at high temperatures
• _______ a period from left to right, the
elements become less metallic and more
nonmetallic in their properties
• Most _____ metals are on left side of table
• Most reactive nonmetals are on right side in
Group __
Representative
Groups
Chapter 5 Section 3
Pg. 139-149
• Why is Hydrogen on the left side of the
periodic table with the active metals?
– It is a nonmetal ___ that seems to have more in
common with the nonmetals in Group 17
• Hydrogen’s location is related to its ________
configuration, not its properties
• _______ electron is an electron that is in the
highest occupied energy level of an atom
– they play a key role in chemical reactions
• Properties vary across a period because the
number of valence electrons ______ from left
to right
• Elements in a group have similar properties
because they have the _____ number of
valence electrons
• Group 1
– Have ______ valence electron and are extremely
reactive
– Found in nature only in compounds because they
are so ______
• The reactivity of alkali metals _________
from the top of Group 1 to the bottom
• Sodium and potassium are stored under oil to
keep them from reacting with the ______ and
water vapor in air
• Group 2
– All have ___ valence electrons
– Harder metals than metals in group 1
• Differences in reactivity among the alkaline
earth metals are shown by the ways they
react with _____
• ______________
– Plays a key role in the process that uses sunlight to
produce sugar in plants
– The center of _______ is magnesium
– A mixture of magnesium and other metals can be
as strong as steel, but much lighter
• Calcium
– Body needs calcium to keep
bones and teeth ______
– Calcium _______: compound of calcium, carbon,
and oxygen- main ingredient in chalk, limestone,
coral, and
pearls
• Group 3
– All have ___ valence electrons
• __________ is the most abundant metal in
Earth’s crust
• Group 4
– 1 nonmetal (carbon), 2 metalloids (silicon,
germanium) and 2 metals (tin, lead)
– Each has ____ valence electrons
• Except for water, most of the compounds in
your body contain _______
• Silicon is the ______ most abundant element
in Earth’s crust
• Group 5
– Has 2 nonmetals (N, P), 2 metalloids (As, Sb), and
1 metal (Bi)
– Wide range of _______ properties
– All have ___ valence electrons
– Nitrogen: nonmetal gas
– Phosphorus: solid nonmetal
– Bismuth: a dense metal
• Besides nitrogen, fertilizers often contain
________
• Group 6
– All have ___ valence electrons
• _______ is the most abundant element in
Earth’s crust
– Complex forms of life need oxygen to stay alive
because it releases the ______ stored in food
– Ozone is another form of oxygen; at ground level
it is an irritant, at upper levels it absorbs harmful
radiation emitted by the sun
• _______ was one of the first elements to be
discovered- found in large natural deposits
• Group 7
– Each has ___ valence electrons
• Despite their physical differences, the
halogens have similar _______ properties
– Highly reactive _______ (fluorine most reactive,
chlorine is a close second)
– React easily with most metals
• Group 8
– Each has ___ valence electrons with the exception
of Helium which has 2
– Colorless and _____ and extremely __________
• Some light bulbs are filled with _____ because
the glowing filament in the bulbs will not react
with argon as it would react with oxygen