Transcript Slide 1

The Periodic Table: Tour of the
Periodic Table – Key Terms
• Main-group elements – ones in sand p-blocks of the table that are
called representative elements
because they have a wide range
of properties.
• See Figure 5 on page 124.
Key Terms 2
• Main group elements have special
sub groups like alkali metals
(Group 1), alkaline-earth metals
(Group 2), halogens (Group 17) &
noble gases (Group 18).
• See Fig. 6 pg 125 for alkali metals
which react with water to make
alkaline solutions (pH > 7.0).
Key Terms 3
• Alkali metals can be cut by a knife
but lose the newly exposed shiny
surface because the metal reacts
with H2O & O in the air.
• See Table 3 page 125 for their
physical properties.
Key Terms 4
• These metals are very reactive
because they only have 1 valence
electron, and losing it results in a
stable electron configuration.
• Transition metal – one that bonds
with electrons in its inner shell
before its outer shell
Key Terms 5
• Ductile – squeezable into wire
• Alloy – solid or liquid mixture of 2
or more metals
• Lanthanide – member of the rareearth series with an atomic # between 58 (cerium) & 71 (lutetium)
Key Terms 6
• Actinide – any element of the
actinide series where its
atomic number falls between
89 (actinium, Ac) through 103
(lawrencium, Lr)
Tour of the Periodic Table:
Things To Do
• Locate the different families of
main-group elements on the
periodic table.
• Describe their characteristic
properties and relate these to
their electron configurations.
Things To Do 2
• Locate other metals on the
periodic table.
• Describe their characteristic
properties and relate these to
their electron configurations.
Tour of the Periodic Table – Main
Group Elements
• S- & p-block elements with regu-
lar electron configurations (EC).
• Same group = same # of valence
electrons whose configurations
are ns1 to ns2p6.
• Here, n is the series or row #.
Main Group Elements 2
• Row # doubles as the energy
level & principal quantum #.
• For example, a Row 3 Group 2
element (Mg) would have an EC
of 3s2.
• Group 16 in this row (Sulfur)
would have an EC of 3s23p4.
Main Group Elements 3
• Since these elements are in the s-
& p-blocks, their valence electrons
occupy s & p orbitals.
• Group 2 alkaline-earth metals are
slightly less reactive because they
have 2 valence electrons.
Main Group Elements 4
• It takes more time and energy
to lose 2 electrons than one.
• Group 17 Halogens are very
reactive because they need
only 1 valence electron to have
a full outermost energy level.
Main Group Elements 5
• Groups 1 & 17 are alike in
needing to move only one
valence electron.
• However the 1st group loses
but the 2nd one gains an
electron.
Main Group Elements 6
• Halogens are the most reactive
nonmetals & react with metals to
form salts like NaCl.
• Calcium is the best know alkalineearth (Group 2) metal; it’s in
bone, limestone, marble & teeth.
Main Group Elements 7
• Noble gases in group 18 are
mostly unreactive not inert.
• They have a full outermost
energy levels but can be made
to react under extreme
circumstances.
Main Group Elements 8
• The strong stability and resultant
low reactivity allow special uses
like filling blimps.
• H is in a solo class because it is
the most common element.
• H’s used to make ammonia, NH3,
which is used to make fertilizer.
Most Elements Are Metals
• Study Figure 11 on page 128.
• Metals share many properties like
being great heat and electricity
conductors, ductile & malleable.
• Transition metals are in the center
of the periodic table, Groups 3-12.
Most Elements Are Metals 2
• Groups of transition metals or d-
block elements do not have the
same # of valence electrons.
• HOWEVER, THE SUM OF THE
OUTER d & s ELECTRONS = THE
GROUP #.
• They can lose 1 to 3 valence
electrons, have lower reactivity
than Groups 1-2 metals but keep
other metal properties.
Most Elements Are Metals 3
• Lanthanides & actinides fill f-
orbitals but are placed toward the
bottom of the table in two rows to
keep the table narrow.
• Lanthanides = name of the 1st of
these rows because in it elements
have atomic #’s that follow
lanthanum.
Most Elements Are Metals 4
• Actinides = name because
elements in the row beneath
lanthanides have atomic #’s that
follow actinium.
• Left to right in these rows,
electrons get added to 4f-orbitals
in the lanthanides but 5f ones in
the actinides.
Most Elements Are Metals 5
• For actinides, the nuclear structure
is more important than electron
configuration.
• This is because their nuclei are
unstable, and as a result they
spontaneously break apart &
cause radioactivity.
• Uranium is the best-known
actinide.
Most Elements Are Metals 6
• Some other properties of metals
include widely varying melting
points with the highest (W,
4322˚C) and among the lowest
ones (Hg, -39˚C).
• They can be mixed to make alloys
that eliminate the disadvantages
of the solo metals.
Most Elements Are Metals 7
• For example, brass is Cu & Zn,
which is harder than Cu and more
resistant to corrosion.
• Sterling silver is mostly Ag with a
little Cu.
• Steel is mostly Fe but has 0.2% 1.5% carbon atoms & usually tiny
amounts of other elements like
Mn and Ni.
Most Elements Are Metals 8
•Consider finding an element
in nature still in its pure
elemental state.
•What does this reveal about
its reactivity?