A Brief History of the Elements

Any pure substance that is made of only one kind of atom Element Any pure substance that is made of only one kind of atom

History of Elements Aristotle Aristotle believed there were four “elements”: air, fire, water, and earth. People during Aristotle’s time period knew of at least nine substances that are defined as elements today.

History of Elements Alchemists Alchemists tried to convert “cheap” metals, like lead, into gold. In doing so, they developed equipment and techniques that enabled them to discover and purify substances.

History of Elements Alchemists Alchemy also had a philosophical, magical, and mystically religious aspect to it.

History of Elements Alchemy was transformed into a real science after the Renaissance. Boyle rejected Aristotle’s elements and defined an element as any substance that cannot be decomposed into simpler substances.

Element Symbols Berzelius proposed element symbols consisting of the first two letters of the element’s Latin name.

Element Symbols In the current periodic table, each symbol still consists of a letter or two from the element’s name. Most of the symbols are derived from the English names instead of the Latin.

Element Symbols You will need to memorize the symbols for several common elements. Page 414

Familiar Elements and Their Symbols aluminum Al copper Cu mercury Hg radium Ra argon Ar fluorine F neon Ne radon Rn arsenic As gold Au nickel Ni silicon Si barium Ba helium He nitrogen N silver Ag bromine Br hydrogen H oxygen O sodium Na calcium Ca iodine I phosphorus P sulfur S carbon C iron Fe platinum Pt tin Sn chlorine Cl lead Pb plutonium Pu tungsten W chromium Cr magnesium Mg potassium K uranium U

Element Symbols Some symbols still use letters from the element’s Latin name. Silver, Ag - argentum Sodium, Na - natrium Iron, Fe - ferrum Lead, Pb - plumbum

Element Symbols Some elements are named for scientists, places, or colors.

Characteristics of Elements Almost all naturally-occurring elements are solids at room temperatures. Two are liquids, and eleven are gases.

Characteristics of Elements Some elements naturally occur as separate atoms. These elements are called monatomic. They are located at the far right of the periodic table.

Characteristics of Elements Some elements exist as molecules consisting of two atoms. These elements are called diatomic.

Characteristics of Elements Hydrogen, nitrogen, oxygen, and the halogens are diatomic molecules. The halogens are the four elements on the right side of the periodic table (shaded light purple).

The Diatomic Molecules Characteristics of Elements The Diatomic Molecules H N O H a l o g e n s

Characteristics of Elements Anytime an element occurs in a molecule with more than two atoms, it is called a polyatomic molecule. Oxygen can form O3 (ozone) or O4 (tetraoxygen). Sulfur can occur as S7, S8, or S12.

Who proposed symbols consisting of the first two letters of an element’s Latin name? Aristotle Berzelius Boyle The Alchemists

Which of the following is not a diatomic molecule? Chlorine Iodine Oxygen Sulfur