Elements & their Properties
Ch. 17
Metals
Metals are elements
that are shiny,
malleable, ductile, and
good conductors of
heat and electricity.
-Everything left of
zigzag.
Group 1: Alkali Metals Characteristics
● Alkali metals are soft metals due to weak
metallic bonding. They can be easily cut
by knife. The hardness of the alkali metals
decreases down the group.
● They have low melting and boiling points.
● They are highly reactive metals.
● Readily lose their two outermost electrons
to form cations with a 1+ charge.
Group 2: Alkaline Earth Metals Characteristics
● shiny.
● silvery-white.
● somewhat reactive metals at
standard temperature and pressure.
● readily lose their two outermost
electrons to form cations with a 2+
charge.
● low densities, low melting points,
low boiling points
Groups 3-12: Transition Elements Characteristics
● they are good conductors of heat and electricity.
● they can be hammered or bent into shape easily.
● they have high melting points (but mercury is a liquid at
room temperature)
● they are usually hard and tough.
● they have high densities.
● Show variable oxidation states (different amounts of
electrons gained or lost)
nonMetals
Hydrogen Characteristics
●
●
●
●
●
Colorless
Odorless
Tasteless
non poisonous gas under
normal conditions on Earth.
It typically exists as a
diatomic molecule, pure
hydrogen is commonly
expressed as “H2“
Group 7A or 17: Halogens Characteristics
● They all form acids when combined with
hydrogen.
● are all fairly toxic
● readily combine with metals to form salts
● have seven valence electrons in their outer
shell
● are highly reactive and electronegative
● all exist as diatomic molecules (two atoms)
when in their pure form
Group 8A or 18: Noble Gas Characteristics
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●
●
●
●
Fairly nonreactive
Complete outer electron or valence shell
Very low electronegativities
Low boiling points
No color, odor, or flavor under ordinary
conditions (but may form colored liquids
and solids)
● Nonflammable
● At low pressure, they will conduct
electricity and fluoresce
Metalloids
Metalloid Characteristics
Metalloids are elements that have some properties of metals and
some properties of nonmetals.
● Form ionic bonds and covalent bonds
● Can conduct electricity better than nonmetals but not as
well as many metals
● Located along the stair step line.
Group 3A or 13: Boron Group
● Boron is used in borax and
boric acid in laundry products
and heat-resistant glass (lab
equipment)
● Aluminum is the most
abundant metal in earth’s crust
● Gallium is used in electronic
components
● Indium and Thallium = very
rare metals
Carbon and its Allotropes
●
●
Carbon, nonmetal, occurs in coal and foods and is essential for life.
Allotrope: different molecular structures of same element.
Silicon and Semiconductors
●
●
Silicon, metalloid, is second only to oxygen in abundance in Earth’s crust.
Found in sand and almost all rocks and soil.
Semiconductors are elements that conduct an electric current under certain
conditions.
Group 4A or 14:
Carbon Group Characteristics
● Have 4 valence electrons,
● Includes nonmetals,
metalloids, and metals
● Tin, metal, is used to coat
other metals to prevent
corrosion.
● Lead is used in car batteries.
Group 5A or 15:
Nitrogen, nonmetal, used to make
ammonia and nitrates. Nitrogen is the 4th
most abundant element in your body.
Phosphorus is a nonmetal that has 3
allotropes. Used for water softeners to
fertilizers, and match heads.
Arsenic and antimony are metalloids, toxic
Bismuth, metal, used in fire sprinkler
heads because of low melting point.
Group 6A or 16: Oxygen Group
● Oxygen, nonmetal, exists in air as
diatomic
● Is essential for life
● Sulfur, nonmetal, combines with
metals to be used in pigments in
paints.
● Selenium is a trace element in diet,
toxic in excess
● Tellurium and polonium, metalloids