The Elements
Periodic Law
Periodic Table
• Dmitri Mendeleev
developed the modern
periodic table. Argued that
element properties are
periodic functions of their
atomic weights.
• We now know from Henry
Moseley that element
properties are periodic
functions of their ATOMIC
NUMBERS.
METALS, METALLOIDS AND NONMETALS
(Label the top PT according to the following classification)
When elements are
arranged in order of
increasing atomic number,
there is a periodic repetition
of their physical and
chemical properties
Noble Gases
• Elements in the same
group generally have
similar chemical properties.
• However, physical
properties are not identical.
Classifying the Elements
According to Chemical Properties
•Now turn to page 784 in your text.
This is the element handboook
(Label the bottom PT according to the following classification)
Metals
•
•
•
•
•
•
Alkali Metals •
Alkaline-Earth
Metals
Transition
Metals
Other Metals
Lanthanides
Actanides
Metaloids
Non-Metals
Same
•
properties •
•
•
Hydrogen
Noble
Gases
Halogens
Other Nonmetals
For each of the element classifications
discussed, you can use the element
handbook to investigate chemical and
physical properties.
The page of the element handbook will
be listed in the top right corner for each
classification discussed.
1
Group 1A: Alkali Metals
786
Group 2A: Alkaline Earth Metals
•Very soft
792
Magnesium
•Slippery appearance
•React with water
violently
•Soft
•Low melting
point
•Very low melting point
•Name comes from
Arabic word for ashes.
•Found only as
Cutting sodium metal compounds in nature.
Transition Elements
798
calcium
Magnesium
oxide
•Very
reactive with
halogens
Colors of Transition Metal
Compounds
•Can have multiple oxidation
states
•Have the typical metal
properties
•Good conductors
•High luster
•Not very reactive
•Form oxides
•Generally hard
Chromium
Iron
Copper
Iron
Cobalt
Nickel
Lanthanides and
actinides
Other Metals
•Considered
transition metals
•Softer than
transitions
•Lanthanides are
known as the
“shiney metals”
•Farily pliable
•Actanides are
considered the
“radioactives”
Copper
Zinc
•Most unreactive
metals
Cerium
Uranium
Aluminum
2
Chlorine gas
Group 7A:
Halogens
•Very reactive
with metals
838
Other Non-metals
808-837
•Properties depend
on element
•Very diverse in
properties
•Most reactive
elements
Phosphorous
•Toxic as
elements
Sodium Chloride
Carbon
Group 8A: Nobel Gases
• Most unreactive
elements due to a full
octet
• All are monatomic
gases at room
temperature
• Clear except Kr (faint
green “glow”)
Nitrogen
Hydrogen
The Hindenburg crash,
May 1939.
Shuttle main engines
use H2 and O2
•Generally does not react
with metals.
•Reacts with non-metals
to form acids
3