Download The Periodic Table - Crestwood Local Schools

Classification of Elements
 What was another pattern of organization
you noticed on the periodic table?
 Physical properties and states
 3 main classifications of elements
 Metals
 Nonmetals
 Metalloids
1. Metals

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Elements that are shiny, smooth and clean
Solid at room temperature
Good conductors of heat and electricity
Malleable
 Hammered flat
into a sheet
 Ductile
 Drawn out into
a wire
1. Metals
 All group B and most group A elements
 Staircase line is divider between metals
and nonmetals (Boron 3A and Astatine
7A)
 ALMOST all elements on left side of table
are metals
 What is the exception?
 Hydrogen
Alkali and Alkaline Earth metals
(Group A)
 What does alkali mean?
 basic
 Alkali metals
 Group 1A (except hydrogen)
 Alkaline earth metals
 Group 2A
 Both alkali and alkaline earth metals are
chemically reactive
 Alkali metals more reactive…why do you think?
 Valence electrons…how many do group 1A elements have?
 Is this stable?
Transition Elements
(Group B)
 2 categories
 Transition metals
 Inner Transition Metals (2 types)
Inner Transition Metals
 Located along the bottom of the periodic table
 2 sets
 Lanthanide series
 Top row of the inner transition elements
 These elements are used as phosphors
 Substances that emit light when struck by electrons
 Where have we seen this before?
 Where do we see this today?
 Actinide series
 Bottom row of the inner transition elements
Transition elements
 All other group B elements that are not
inner transition elements
 Basically the Group B elements we see on
the actual periodic table…
 Think of it as the ‗continental US‘
3 main classifications
of elements
• Metals
• Nonmetals
• Metalloids
2. Nonmetals
 Occupy the upper right side of the periodic

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table
Usually gases
Brittle, dull-looking solids
Poor conductors of heat and electricity
Bromine (Br) is the only nonmetal that is
liquid at room temperature
Important nonmetals
 Group 7A
 Halogens
 Highly reactive elements
 What does this mean?
 Why are they highly reactive?
 Look at the valence electrons
 Group 8A
 Noble gases
 Highly unreactive
 Why?
 8 valence electrons
3 main classifications
of elements
• Metals
• Nonmetals
• Metalloids
3. Metalloids
 Border the stair-case line
 Elements with physical and chemical
properties of both metals and non-metals
 Silicon and germanium
 Two of the most important metalloids
 Anyone know why?
 Used in computer chips and solar cells
Everyday Examples
 Metals?
 Jewelry
 Pot and pans
 Cars
 Nonmetals?




Air we breath
Nitrogen
Neon signs
Diamonds
 Metalloids?
 Computer chips
Everyday Examples
 Metals?
 Jewelry
 Pot and pans
 Cars
 Nonmetals?




Air we breath
Nitrogen
Neon signs
diamonds
 Metalloids?
 Computer chips
Everyday Examples
 Metals?
 Jewelry
 Pot and pans
 Cars
 Nonmetals?




Air we breath
Nitrogen
Neon signs
diamonds
 Metalloids?
 Computer chips
Everyday Examples
 Metals?
 Jewelry
 Pot and pans
 Cars
 Nonmetals?




Air we breath
Nitrogen
Neon signs
diamonds
 Metalloids?
 Computer chips
Everyday Examples
 Metals?
 Jewelry
 Pot and pans
 Cars
 Nonmetals?




Air we breath
Nitrogen
Neon signs
diamonds
 Metalloids?
 Computer chips
Everyday Examples
 Metals?
 Jewelry
 Pot and pans
 Cars
 Nonmetals?




Air we breath
Nitrogen
Neon signs
diamonds
 Metalloids?
 Computer chips
Everyday Examples
 Metals?
 Jewelry
 Pot and pans
 Cars
 Nonmetals?




Air we breath
Nitrogen
Neon signs
diamonds
 Metalloids?
 Computer chips
Organizing the Elements by
Electron Configuration
Electron configuration determines the
chemical properties of an element.
 Recall electrons in the highest principal
energy level are called valence
electrons.
Organizing the Elements by
Electron Configuration
 All group 1 elements have one valence
electron.
 All group 2 elements have two valence
electrons.
Organizing the Elements by
Electron Configuration
Organizing the Elements by
Electron Configuration
 The energy level of an element‘s valence electrons
indicates the period on the periodic table in which it is
found.
 The number of valence electrons for elements in
groups 13-18 is ten less than their group number.
 After the s-orbital is filled, valence electrons occupy the
p-orbital.
 Groups 13-18 contain elements with completely or
partially filled p orbitals.
Organizing the Elements by
Electron Configuration
Organizing the Elements by
Electron Configuration
Organizing the Elements by
Electron Configuration
 The d-block contains the transition metals and is
the largest block.
 There are exceptions, but d-block elements usually
have filled outermost s orbital, and filled or partially
filled d orbital.
 The five d orbitals can hold 10 electrons, so the dblock spans ten groups on the periodic table.
Organizing the Elements by
Electron Configuration
 The f-block contains the inner transition metals.
 f-block elements have filled or partially filled
outermost s orbitals and filled or partially filled 4f and
5f orbitals.
 The 7 f orbitals hold 14 electrons, and the inner
transition metals span 14 groups.
Periodic Trends
Objectives:
 Compare period and group trends of
several properties.
 Relate period and group trends in atomic
radii to electron configuration
Periodic Trends
Atomic Radius
Atomic radius – is determined by the amount of
positive charge in the nucleus and the number of
valence electrons of an atom. It is usually
measured in picometers (10-12).
 For metals, atomic radius is half the distance
between adjacent nuclei in a crystal of the
element.
 For nonmetals, the atomic radius is the distance
between nuclei of identical atoms.
Atomic Radius
Atomic Radius
The periodic trend: decreases from left to right
(periods) and increases top to bottom
(groups) due to the increasing positive charge
in the nucleus.
Atomic Radius
Atomic Radius
 Atomic radius generally increases as you move
down a group.
 The outermost orbital size increases down a
group, making the atom larger.
 Valence electrons are not shielded from the
increasing nuclear charge because no additional
electrons come between the nucleus and the
valence electrons.
Ionic Radius
Ions – atom(s) that gain or lose one or more electrons
to form a net charge.
Ionic radius is the radius of a charged atom.
 When atoms lose electrons and form positively
charged ions, they always become smaller.
 Lost electrons are usually valence electrons and
could leave the outer orbital empty and therefore
smaller.
 Electrostatic repulsion between remaining
electrons decreases and pulls closer to nucleus.
Ionic Radius
 When atoms gain electrons and forms a
negatively charged ion, they become larger.
 Increased electrostatic repulsion increases
distance of outer electrons.
Ionic Radius
Periodic Trend:
 Radius of an ion decreases from left to right
(periods) until charge changes and then the
radii increases dramatically.
 After the change, the radius continues to
decrease.
 Ionic radii increases top to bottom (groups)
until change in charge.
Ionic Radius
Ionic Radius
Ionic Radius
Ionization Energy
Ionization energy is the energy needed to
remove an electron from the positive charge of
the nucleus of a gaseous atom – how strongly
a nucleus holds on to an electron.
 First ionization energy is the energy required to
remove the first electron.
 Removing the second electron requires more
energy, and is called the second ionization
energy.
Ionization Energy
 Atoms with large ionization energies have a
strong hold of its electrons and are less likely
to form positive ions.
 Atoms with low ionization energies lose their
outer electrons easily and readily form positive
ions.
 The ionization at which the large increase in
energy occurs is related to the number of
valence electrons.
Ionization Energy
Periodic Trend:
 First ionization energy increases from left to right
across a period.
 First ionization energy decreases down a group
because atomic size increases and less energy is
required to remove an
electron farther from
the nucleus.
Ionization Energy
 The octet rule states
that atoms tend to
gain, lose or share
electrons in order to
acquire a full set of
eight valence
electrons.
 The octet rule is
useful for predicting
what types of ions an
element is likely to
form.
Trends in Ionization Energy
Low Energy = Easier to remove electron
High Energy = Difficult to remove electron
Ionization Energy
Shielding Effect
Electronegativity
Electronegativity of an element indicates
its relative ability to attract electrons in a
chemical bond.
Measured in Paulings: numbers 4 and less.
Electronegativity
 Ability to attract
An electron
Forms a Anion
X -> X-
Electronegativity
Periodic Trend: electronegativity decreases down a
group and increases left to right across a period.
Boiling Point
Boiling Point Trends
The Big Bang Theory
-Georges Lemaitre came up with
the Big Bang Theory in 1921
The Big Bang Theory:
• Matter from all the universe
came from a very hot central
point.
• Sooner or later, the central
point began to cool…
• 15 billion years ago those
atoms were drawn together by
gravity.
• This region exploded and
matter was thrown outward
Evidence for Big Bang Theory
 In 1929, Edwin Hubble
discovered that the universe
is expanding.
 The universe is filled with
radiation that is left-over
from the Big Bang called
Cosmic Microwave
Background Radiation,
which was discovered in the
1960‘s
 Red shift- tells us that
objects are moving away
from us.
Big Bang Theory Weaknesses
 Many Christians believe that God created the
Earth, and all the universe. Many criticize the Big
Bang Theory and come up with many
explanations on why it‘s not correct.
 There are also two other scientific theories
explaining how the universe could have been
created.
 If the universe really was created by an explosion,
and was spread evenly, then there shouldn‘t be
clusters of galaxies, stars, planets, etc.
Random Facts About the
Big Bang Theory
 If we were to look at the universe one
second after the Big Bang, what we would
see is a 10 billion degree sea of neutrons,
protons, electrons, (and such things as
anti-electrons, photons, and nutrions).
 Some scientists believe that the universe
may contract back to a central point.
Scientists like to call this the ―Big Crunch‖.
Natural Elements
 Hydrogen and Helium were the first to form after
the explosion
 E = mc2
When helium formed by the fusion
of hydrogen atoms, some mass was lost as
energy.
 Fusion reactions release an enormous quantity of
energy—enough to maintain the heat at the center
of a star
 The continued fusion of atoms formed the other 93
natural elements.
Nuclear Fusion
4
1H
-----------> 4He
occurs in the core of stars
Fusion in SuperGiant Stars
 Betelgeuse is a red giant star in Orion
that is currently fusing Helium
and will become a supernova
Size comparisons video
3 4He --------->
12C
Elemental Abundance
1. Hydrogen
2. Helium
3. Oxygen
4. Carbon
Rare earth elements
Alchemy
Synthetic Elements
Transmutation:
 The changing of
one element into
another
 Alchemists tried to
change such things
as lead into gold.
 Modern chemists
have produced
elements with larger
nuclei using
equipment called
particle accelerators
Lawrence‘s Cyclotron
The first particle accelerator
Superheavy Elements
 Transuranium Elements
 Produced by nuclear collisions
Key Concepts
 The elements were first organized by increasing
atomic mass, which led to inconsistencies. Later,
they were organized by increasing atomic
number.
 The periodic law states that when the elements
are arranged by increasing atomic number, there
is a periodic repetition of their chemical and
physical properties.
 The periodic table organizes the elements into
periods (rows) and groups (columns); elements
with similar properties are in the same group.
Key Concepts
 Elements are classified as either metals, nonmetals, or
metalloids.
 The periodic table has four blocks (s, p, d, f).
 Elements within a group have similar chemical properties.
 The group number for elements in groups 1 and 2 equals
the element‘s number of valence electrons.
 The energy level of an atom‘s valence electrons equals its
period number.
Key Concepts
 Atomic and ionic radii decrease from left to right across
a period, and increase as you move down a group.
 Ionization energies generally increase from left to right
across a period, and decrease as you move down a
group.
 The octet rule states that atoms gain, lose, or share
electrons to acquire a full set of eight valence
electrons.
 Electronegativity generally increases from left to right
across a period, and decreases as you move down a
group.