Transcript AP Chemistry Chapter 7

PERIODIC LAW – THE
PHYSICAL AND CHEMICAL
PROPERTIES OF THE
ELEMENTS ARE PERIODIC
FUNCTIONS OF THEIR
ATOMIC NUMBERS.
The Periodic Law
Mendeleev’s Periodic Table
Dmitri Mendeleev
MENDELEEV DID THE PERIODIC
TABLE BEFORE THE NOBLE GASES
WERE DISCOVERED BY SIR RAMSEY
Chinese Periodic Table
A Spiral Periodic Table
Triangular Periodic Table
“Mayan”
Periodic
Table
Giguere Periodic Table
Orbital filling table
Periodic Table with Group # and Names
KNOW THESE!!!!!!
HINT HINT
OCTETS
The Properties of a Group:
the Alkali Metals
Easily lose valence
electron
(Reducing agents)
React violently with
water
Large hydration energy
React with halogens to
form salts
Properties of Metals
 Metals are good
conductors of heat and
electricity
 Metals are malleable
 Metals are ductile
 Metals have high
tensile strength
 Metals have luster
Examples of Metals
Potassium, K
reacts with
water and
must be
stored in
kerosene
Copper, Cu, is a relatively soft
metal, and a very good electrical
conductor.
Zinc, Zn, is
more stable
than potassium
Mercury, Hg, is the only
metal that exists as a
liquid at room temperature
Properties of Nonmetals
Carbon, the graphite in “pencil lead” is
a great example of a nonmetallic
element.
 Nonmetals are poor conductors of
heat and
electricity
 Nonmetals tend to be brittle
 Many nonmetals are gases at room
temperature
Examples of Nonmetals
Sulfur, S, was
once known as
“brimstone”
Graphite is not the only
pure form of carbon, C.
Diamond is also carbon;
the color comes from
impurities caught within
the crystal structure
Microspheres
of phosphorus,
P, a reactive
nonmetal
Properties of Metalloids
Metalloids straddle the
border between metals
and nonmetals on the
periodic table.
 They have properties of both metals
and nonmetals.
Metalloids are more brittle than
metals, less brittle than most
nonmetallic solids
 Metalloids are semiconductors of
electricity
Silicon, Si – A Metalloid
 Silicon has metallic luster
 Silicon is brittle like a nonmetal
 Silicon is a semiconductor of
electricity
Other metalloids include:





Boron, B
Germanium, Ge
Arsenic, As
Antimony, Sb
Tellurium, Te
Determination of Atomic Radius:
Half of the distance between nucli in
covalently bonded diatomic molecule
"covalent atomic radii"
Periodic Trends in Atomic Radius
Radius decreases across a period
Increased effective nuclear charge due
to decreased shielding
Radius increases down a group
Addition of principal quantum levels
Table of
Atomic
Radii
Ionization Energy - the energy required to
remove an electron from an atom
Increases for successive electrons taken
from the same atom
ATOM + ENERGY  A+ + eTends to increase across a period
Electrons in the same quantum level do
not shield as effectively as electrons in
inner levels
Tends to decrease down a group
Outer electrons are farther from the nucleus
Table of 1st Ionization Energies
Another Way to Look at Ionization
Energy
Electron Affinity - the energy
change associated with the addition
of an electron
ATOM + e-  A- + ENERGY
Affinity tends to increase across a period
Affinity tends to decrease as you go down
in a period
Electrons farther from the nucleus
experience less nuclear attraction
Some irregularities due to repulsive
forces in the relatively small p orbitals
Table of Electron Affinities
Ionic Radii
Cations
Anions
Positively charged ions
Smaller than the corresponding
atom
Negatively charged ions
Larger than the corresponding
atom
MOST REACTIVE METAL:
FRANCIUM
MOST REACTIVE NONMETAL
FLOURINE
Electronegativity
A measure of the ability of an atom
in a chemical compound to attract
electrons
Electronegativities tend to increase
across a period
Electronegativities tend to decrease
down a group or remain the same
Periodic Table of Electronegativities
Summation of Periodic Trends
ELECTRONEGATIVITY
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