Chapter 6Developing The Periodic Table

Each element has its own symbol that begins with a capital letter. Any other letters in the symbol are lower case.

Latin Names

Element Symbol Latin Name

Sodium Na Natrium

Copper Cu Cuprum

Gold Au Aurum

Iron Fe Ferrum

Silver Ag Argentum

Lead (Pb)“The Metal That Destroyed Rome”

• “Lead poisoning contributed to the fall of Rome,” such is the judgment of certain toxicologists.

Lead (Pb) Z = 82

• Plumbum (Pb) • Plumber

The Lost Franklin Expedition

Its New, Its Canned, Its Poisoned

This old tin can was full of potatoes and was part of the food supply on Sir John Franklin's ships. Many of these tin cans, discarded by the sailors, have been found on Beechey Island. In those days, cans were just starting to be used as a means of preserving food. People did not understand that the lead from the solder seam would give a person lead poisoning and could kill them. It is believed that many of the men of the Franklin Expedition died in this way.

Mendeleev

• In 1869, Dmitri Mendeléev created the first version of the periodic table.

Mendeleev

• He arranged the elements in order of increasing atomic mass and grouped them by similarity of properties.

Mendeleev

• This allowed him to predict the properties of new elements.

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Henry Moseley• Developed method of

measuring the atomic number of elements.

• This resulted in a more accurate positioning of elements in the Periodic Table.

• Predicted the existence of elements 43, 61, 72, and 75.

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Gallipoli

• At the age of 27, having volunteered to serve in the British Army in WWI, Moseley was killed by a sniper.

• When WWI started, he volunteered for active duty and became an officer in the signal corps. At the time of his death, he was the most promising physicist of his time. Even a newspaper in Germany (the enemy of Britain in the war) printed the headline “Ein schwerer Verlust” (“A heavy loss—for science”) when he died in Gallipoli.

• It is speculated that because of Moseley's death in the War that the British and other world governments began a policy of no longer allowing their scientists to enlist for combat.

• Many speculated that he should have won the Nobel Prize, but was unable to because it is only awarded to the living.

Metals, Nonmetals, Metalloids

Groups and Periods

• The vertical columns in the periodic table are called groups.

• Rows in the periodic table are termed periods.

• Elements with similar properties within the periodic table are grouped into a family.

Families on the Periodic Table

• Columns are also grouped into families.

• Families may be one column, or several columns put together.

• Families have names rather than numbers. (Just like your family has a common last name.)

Alkali Metals• 1st column on the periodic

table (Group 1) not including hydrogen.

• Most reactive family of metals, always combined with something else in nature (table salt).

• Low density metals (Li, Na and K are less dense than water).

• that are soft enough to cut with a butter knife.

Alkaline Earth Metals• Second column on the periodic

table. (Group 2)• Second most reactive family of

metals, always combined with nonmetals in nature.

• All of the alkaline earth metals are found in compound form within the earth's crust.

• Several of these elements are important mineral nutrients (such as Mg and Ca).

Transition Metals

• Elements in groups 3-12

• Less reactive harder metals

• Includes metals used in jewelry and construction.

• Metals used “as metal.”

Oxygen Family or Chalcogens

• Elements in group 16• Oxygen is necessary

for respiration.• Many things that

stink, contain sulfur (rotten eggs, garlic, skunks,etc.)

Halogens• Elements in group 17• Most reactive of the

nonmetals.• Always found combined with

other element in nature.• Have a strong unpleasant

odor and are poisonous (have been used as chemical weapons).

• In low doses can be used as disinfectants (chlorine in drinking water and in pools).

The Noble Gases

• Elements in group 18• All are gases.• VERY non-reactive.• Have a full outer

energy level.

The Octet Rule

• The octet rule states that an element's outer energy level is full and most stable when it contains eight electrons.

• This stability is the reason that the noble gases are so non-reactive.

Exception to the Octet Rule

• The first energy level can only hold two electrons and so elements such as H and He follow a “duet rule”.

Rare Earth Elements

• The thirty rare earth elements are composed of the lanthanide and actinide series.

• The rare earth elements are metals.

• Many of these elements are synthetic or man-made.

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