Organization of the Periodic Table

Groups

By Ms Dobbs

Group 18 = Noble gases

• also know as inert gases

• very unreactive -- No known stable compounds have been produced from He, Ne, Ar. Xe Kr, and Rn have extremely low reactively , and will form compounds under extreme conditions.

• 8 electrons in the outer most energy levels (filled s and p orbital)

Noble Gases

• Because of this e- configuration, noble gases are very stable and resist combining with other elements.

• Other elements gain or lose e- to achieve electron configuration like the noble gases.

• Noble gases are used in signs (Ne, Ar) and balloons (He).

• Rn is the only radioactive gas at room T/P.

Noble Gases

Group 1 = Alkali Metals

• Name comes from the Arabic work al-qali meaning ashes because it was discovered these elements make alkali (basic) solutions.

• Very reactive metals

• Will react with oxygen in air and must be stored in jars of oil or kerosene.

• Very soft and can be cut with a knife

Alkali Metals

• Have one electron in the outermost electron energy level (s)

• This electron configuration is what makes the metals so reactive.

• Are good conductors of electricity.

Alkali Metals

Alkali Metals

This sample of uraninitecontains some franciumbecause of a steady-statedecay chain. An estimatesuggests there is about 10-20 grammes of francium(about 1 atom!) at any onetime.

Group 2=Alkaline Earth Metals

• Tend to be harder, denser, stronger, and have high melting points than group 1

• Reactive but not has reactive as alkali metals

• have 2 electrons in outermost electron energy level (s)

Alkaline Earth Metals

• This electron configuration is what makes this group reactive.

• Conduct electricity

Alkaline Earth Metals

Alkaline Earth Metals

Groups 3-12=Transition Elements

• All are considered metals• Are harder, denser, and have

higher melting points than Groups 1 and 2

• Hg is the exception• These will conduct electricity.

Mercury: liquid at room Tlow melting point

Group 17 = Halogens

• Most are gases

• very reactive

• will combine with group 1 elements very readily

• 7 electrons in their outermost electron energy level (s and p)

Halogens

• This electron configuration is what makes the elements reactive.

• Halogens do not conduct electricity.

Halogens

Halogens

This sample of uranite containsa vanishingly small amountof astatine. The longest-livedisotope, 210At, has a half-lifeof only 8.3 hours. There areabout 20 isotopes known, allof which are radioactive.Astatine is a halogen andpossibly accumulates in thethyroid like iodine.

Groups 1,2,13-18 = Main Block Elements

• These represent a wide range of chemical and physical prop.

• Si and O account for 4 out of 5 atoms on Earth’s surface.

Lanthanide Series

• Elements 57 thorough 71.

• These are shiny, reactive, metals.

• These have electrons in the 4f orbital.

Lanthanide Series

Actinide Series

• Elements 89 through 103

• All have an unstable arrangement of protons and neutrons

• This makes them radioactive

Actinide Series

This sample ofuraninite containssome about 10-9 g ofactinium at any one time.

Hydrogen: group unto itself

• Most common element in the universe

• Behaves like no other element

• will react with just about any other element

• rarely found uncombined

Hydrogen