Chapter 17
Elements and Their Properties
1. Metals
a. Metals – elements that are shiny, malleable, ductile, and good conductors of heat and
electricity.
i. Metals are solids at room temperature, except for mercury which is a liquid.
ii. Malleable – can be hammered or rolled into sheets
iii. Ductile – can be drawn into wires.
iv. On the periodic table, metals are located on the left of the stair case. (blue)
b. Metallic Bonding – positively charged metallic ions are surrounded by a sea of
electrons.
i. Metals tend to give up electrons easily because they are not strongly held by
the protons in the nucleus.
ii. Metals tend to bond with nonmetals and form ions. They are more stable
when ions are formed.
iii. When a metal and nonmetal bond together, they form a bond called an ionic
bond.
1. Example: Sodium and Chlorine, Lithium and Fluorine
c. Alkali Metals
i. Group 1 metals are called alkali metals.
1. They are softer than most metals and are the most reactive
2. They do not occur naturally in their elemental form.
3. Alkali metals have one electron in their outer level.
4. Radioactive element – nucleus breaks down and gives off particles
and energy.
d. Earth Metals
i. Group 2 metals are called alkaline earth metals
1. They combine readily with other elements and do not occur naturally
in their elemental form.
2. Group 2 metals contain two electrons in their outer level.
e. Transition Metals
i. Groups 3 to 12 are known as the transition metals.
1. Transition metals get their name as they are ‘in transition’ from
groups 2 to groups 13 through 18.
a. Transition metals often form colored compounds
2. Nonmetals
a. Nonmetals – elements that are usually gases or solids at room temperature.
i. Solid nonmetals are not malleable or ductile, but brittle or powdery.
ii. Nonmetals are poor conductors of heat and electricity, because electrons are
not free to move.
iii. Nonmetals are found to the right of the stair-step line, except for hydrogen
which is in group 1.
iv. Group 18 are the noble gases, which are all nonmetals.
1. The only exist as isolated atoms.
2. They are stable due to having their outermost energy levels are full.
3. An electric current will cause noble gases to glow; i.e. neon lights.
v. Group 17 are the halogens, these are also nonmetals except for astatine.
vi. Nonmetals become negative ions when they gain electrons. When bonded to
other nonmetals, they share electrons, and form a covalent bond.
b. Halogens
i. Fluorine, Chlorine, Bromine, Iodine, and Astatine are known as the halogens
and make up Group 17.
ii. They are very reactive in their elemental forms.
iii. Each atom in the halogen group has seven outer electrons, and only one is
needed to complete their level.
1. Bonding with a metal to gain an electron, forms an ionic compound
called a salt.
iv. Fluorine is the most chemically active of the nonmetal elements
1. Fluorides are added to toothpastes and city water systems to prevent
tooth decay
2. Hydrofluoric acid (hydrogen and fluoride) is used to etch glass and
frost the inside of light bulbs. Also used in making semiconductors.
v. Chlorine is the most abundant halogen
1. Obtained from seawater at ocean-salt recovery sites
2. Used to disinfect water, and used to whiten flour, clothing, and
paper.
vi. Bromine is the only nonmetal that is a liquid at room temperature.
1. It is extracted from compounds in seawater, and once used in
cosmetics and as flame retardants.
2. Bromine compounds absorb fluorescent light and emits a reddish
visible light. Tatine
vii. Iodine is a solid and room temperature and obtained from seawater.
1. Iodine sublimes at room temperature and turns purple. It is also
essential in your diet.
2. Iodine is also used as a disinfectant.
viii. Astatine is a rare radioactive element, and last in the halogen group.
3. Mixed Groups
a. Metalloids – elements that have some properties of metals and some properties of
nonmetals.
i. They can conduct electricity better than most nonmetals but not as well as
many metals.
ii. They are located along the stair-step line. Groups 13 through 17 are mixed
groups and contain metals, nonmetals, and metalloids.
b. Group 13 consists of boron, aluminum, gallium, indium, and thallium (3 electrons in
outer shell)
i. Boron is found in borax and boric acid, used a water softener in laundry
products, and as a mild antiseptic. It is also used to heat-resistant glass.
ii. Aluminum is the most abundant metal in the Earth’s crust. It is used on softdrink cans, foil, pans, bicycle frams, and airplanes.
iii. Gallium is used electronic components
iv. Indium and Thallium are rare metals
c. Group 14 consists of carbon, silicon, germanium, tin, and lead (4 electrons in the
outer shell)
i. Carbon is a nonmetal and occurs as a element in coal, and compound in oil,
natural gas, and foods. All organic compounds contain carbon, but not all
carbon compounds are organic
1. Carbon is considered an allotrope, element that has different
molecular structures; diamond and graphite.
ii. Silicon is a metalloid, and is second only to oxygen in abundance in the
Earth’s crust.
1. Silicon is found in sand, and in almost all rocks and soil.
2. Silicon is the main component in semiconductors – elements that
conduct an electric current under certain conditions
iii. Germanium is used to make semiconductors
iv. Tin is a metal used to coat other metals to prevent corrosion, and can be
combined with other metals to make bronze and pewter.
v. Lead was once widely used in pain, but it is no longer used due to it being
toxic. Lead is also used in car batteries.
d. Group 15 has the elements nitrogen, phosphorus, arsenic, antimony, bismuth (5
electrons in the outer shell)
i. Nitrogen is a nonmetal used to make ammonia and nitrates, commonly found
in fertilizers. It is the fourth abundant element in your body.
ii. Phosphorus is a nonmetal with three allotropes. Compounds are used for
water softeners to fertilizers, they are also used in match heads and find
china.
iii. Arsenic and Antimony are metalloids. Arsenic is used in some
semiconductors, and in paints, but no longer because it is toxic. Antimony is
used to lower their melting points.
iv. Bismuth is an emtal, and used in automatic fire-sprinkler heads.
e. Group 16 contains oxygen, sulfur, selenium, tellurium, and polonium (6 electrons in
outer shell)
i. Oxygen is a nonmetal always exists as O2. Oxygen is found in ozone, water,
and in hydrogen peroxide.
ii. Sulfur is a nonmetal that is used for paint pigments. Selenium is found in
multivitamins. Tellurium and polonium are metalloids.
f.
Transuranium elements, elements that contain more than 92 protons, and are
synthetic and radioactive.
Chapter 17 Vocabulary
Allotrope – different molecular structures of the same element
Diatomic Molecule - a molecule that consists of two atoms of the same element, joined by a covalent
bond
Ductile – property of metals and alloys that allows them to be drawn into wires.
Metal – element that is shiny, malleable, ductile, and a good conductor or heat and electricity.
Metallic Bonding – occurs because some electrons move freely among a metal’s positively charged ions,
explains properties such as ductility and the ability to conduct electricity.
Metalloid – element that shares some properties with metals and some with nonmetals
Nonmetal – element that usually is a gas or a brittle solid at room temperature is not malleable or ductile,
is a poor conductor of heat and electricity, and typically is not shiny.
Radioactive Element – element, such as radium, whose nucleus breaks down and emits particles and
energy.
Semiconductor – material that conducts an electric current under certain conditions.
Transition element – elements in groups 3 through 12 of the periodic table; occur in nature as
uncombined elements and include the iron triad and coinage metals
Transuranium element – elements having more than 92 protons, all of which are synthetic and unstable