Chemical Groups and Families

Group 1-Alkali Metals

Li

Na

K

Rb

Cs

Fr

shiny solids, malleable, ductile

good conductors of electricity

low densities, low melting points

soft enough to be cut with a knife

intense chemical reactivity

reacts readily with air and water

reactivity increases as you go down the group

Na and K most abundant of family (rank 7th and 8th by mass in earth’s crust)

Never found as free elements in nature

Called “Alkali” because they form basic solutions when react with water

Na + H2O NaOH + H2

Group 2-Alkali Earth Metals

Mg

Ca

Sr

Ba

Ra

higher densities and melting points than group 1

also form basic solutions with water

almost as reactive as group 1

Ca, Sr, Ba and Ra react w/water

also not found in nature in elemental state

Ca & Mg most abundant of family (rank 5th and 6th by mass in earth’s crust)

Be differs from others: very high melting point and as strong as steel

Be

Transition Metals

Transition Metals as a Group

Play an important role in living organisms; Co found in vitamin B12, Fe is an essential part of hemoglobin

Many also valuable as strong, structurally useful materials; Fe primary building material, Cr protective coating on metals, Ag and Au used for coins and jewelry

Vary greatly in abundance; Fe and Ti rank 4th an 10th by mass in Earth’s crust. Pt and Ir are very rare

Transition Metals as a Group

Properties vary from family to family

Most have high densities (this is why they are called the “heavy metals”)

Most have high melting points

Most are good conductors of electricity

Most are malleable

Many form more than one ion

BRITTLE

DUCTLE

LOW MELTING PTS

Inner Transition Metals

Lanthanides

Elements of the 4f series

Very similar to one another because they all have the same number of valence electrons

All readily form 3+ ions (ALL considered part of group 3)

Soft, silvery metals

Only somewhat less reactive than group 2

React with air and slowly with water

Widely distributed in nature, but generally occur together; hard to separate

Little commercial importance

Lanthanides

Europium is used in television tubes to produce the red color

Lanthanium used in studio carbon arc lighting and projection lenses in movie industry

Cerium-catalyst used in self cleaning ovens

Ytterbium used to strengthen stainless steel knifes

Promethium used as a nuclear powered battery

Actinides Elements of the 5f series

All Isotopes of these elements are RADIOACTIVE

Only Th and U occur in nature

All others are artificial, produced by nuclear bombardment reactions

Plutonium salts used for coloring glass and enamels

Americium used in smoke alarms

Uranium nitrate compound used in photographic toners

BORON Group

B

Al

Ga

In

Tl

All form 3+ ions

Al is most important; 3rd most abundant element in Earth’s crust

Most Al occurs in ores and compounds in nature; has to be extracted

Al has low density, but when alloyed with other metals is quite strong and does not corrode

Many commercial uses

Boron used for heat resistant glass and eye disinfectant

Ga used in cell phones

Bauxite: Aluminum ore

NITROGEN Group

N

P

As

Sb

Bi

N and P are non-metal; As and SB are semi-metals and Bi is a metal

N makes up approx 80% earth’s atmosphere

N a gas at STP

P compounds with O very important; phosphoric acid

As used shotgun pellets and metal mirrors

Sb used as a solder and ceramic glazes

Bi used as an antacid

CARBON Group

C

Si

Ge

Sn

Pb

Carbon is a non-metal; Si and Ge are semi-metals and Sn and Pb are metals

Carbon widely distributed throughout the Earth’s crust

Compounds of C and H are called hydrocarbons; fuels

Compounds of C called “organic”

CO2 byproduct of human respiration and necessary for plant growth

Si 2nd most abundant element in Earth’s crust; sand

Si also major component of sand

CARBON Group (con’t)

C

Si

Ge

Sn

Pb

Si and Ge are semi-metals; semi-conductors; used to make transistors, solar cells and computer chips

Sn and Pb very common and used for hundreds of years

Sn used to coat steel cans

Pb used in pipes and car batteries

Compounds containing lead ions have been linked to cancer, so not used as much any more

OXYGEN GROUP

O

S

Se

Te

Po

Oxygen most abundant element on earth

The largest source of elemental oxygen is atmosphere

Oxygen also found in compounds called oxides

Elemental oxygen exists as both O2 and O3 (ozone). Ozone has strong, irritating odor and is considered a pollutant. It attacks structural materials and plant/animal tissue.

Ozone absorbs high energy UV radiation from sun

OXYGEN GROUP

O

S

Se

Te

Po

Sulfur occurs pure in nature-known as brimstone

Also occurs in compounds such as FeS2 known as “fools gold”

Many sulfur compounds have unpleasant odor. Sulfur compound added to natural gas to detect leaks

Largest use of sulfur is production of Sulfuric acid. Sulfuric acid has many uses, most commonly lead storage batteries

Selenium copies used in photocopiers

Polonium used in radioactive power

Halogens

F

Cl

Br

I

At

Name Halogen comes from Greek for “Salt Former”; reaction of most metals with halogens form salts

Highly reactive with metals and most non metals

Do not occur as free elements in nature

F very corrosive gas; most reactive of all non-metals

Cl most industrially used

At is very rare; all isotopes are radioactive

NOBLE GASES

He

Ne

Ar

Kr

Xe

Mostly non-reactive

Ar most abundant; 1% of Earth’s atmosphere

Discovered after many of other elements because they do not form compounds

Some Xe compounds have been formed, but they are not very stable

Rn

HYDROGEN

H Typically shown listed with Group 1 but actually a non-metal, colorless, odorless gas

So light it escapes the gravitational pull of the earth, so rare in atmosphere

Most of Earth’s hydrogen found combined with oxygen in water

Also frequently combined with carbon. Hyrocarbons-class of compounds containing hydrogen and carbon. All fuels are hydrocarbon (coal, petroleum, natural gas) as well as plants and animals. (Term “Fossil Fuels” refers to petroleum that is broken down dinosaurs)

9th most abundant element on Earth’s surface. (Crust, water, atmosphere)

Most abundant element in universe

Elemental hydrogen obtained commercially from hydrocarbons

Largest commercial use is in manufacture of ammonia (NH3) which is used in fertilizers

Also used to prepare organic compounds like Methanol and Ethanol. Methanol is used as a fuel in race cars. Ethanol is currently used as a fuel in some corn producing states.

Currently investigating using H fuel cells to power cars

H