Periodic Table Facts

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Compact Periodic Table Table Layout The periodic table is normally presented in a compressed form with Transition Metals the Lanthanides (elements 57-71) and Actinides (elements 89-103) in separate rows below the rest of the table. This is A. Earth Metals Metals Earth A. done to make the table more Lanthanides compact. In the extended table, Actinides shown below, these elements are inserted in their proper position between the Alkaline Earth Metals and the Transition Metals.

Extended Periodic Table

Transition Metals Lanthanides

A. Earth Metals Metals Earth A. Actinides

increasing mass How Small Are Atoms? Atoms are very, very small. To similar understand how small atoms are, start properties by looking at a meter stick. A meter can be divided into 1000 smaller lengths called millimeters. Now think of that millimeter and divide it into 1000 smaller lengths called micrometers. Now think of that micrometer and Periodic Trends divide it into 1000 even smaller lengths Dmitri Mendeleëv organized elements called nanometers. One nanometer is in the Periodic Table according to large enough for about 5 carbon their mass and reactive properties. He atoms.

recognized that some elements had It would take 7,000,000 (7 million) similar properties, so he placed them carbon atoms stacked on top of each in the same column. He placed the other to be the thickness of a dime. elements from left to right in order of increasing mass. Mendeleëv left It would take 120,000,000 (120 million) spaces in his original table for carbon atoms to cross the face of elements that hadn’t yet been a dime. discovered.

Element Names Non- Most names come from words describing M Metals e the characteristics of the element such ta llo as its color, texture, origin, etc. Most Metals id s descriptive names are from Greek and Latin words, but some are from other languages like Swedish or German. Other sources of names are people (real or mythological), places, or astronomical What’s a Metal? bodies. Most of the elements in the Periodic Table are metals. This means they are shiny, The atomic symbol is always written as can be molded, stretched or shaped, one or two letters with only the first letter and transfer heat or electricity. Some capitalized. The names of elements are elements are non-metals, which means not capitalized.

they don’t have these properties. Still carbon [C]—from Latin, carbo, means fewer are metalloids, which means they “charcoal”; known to the Ancient World have some metallic properties. chlorine [Cl]—from Greek, chloros, means “greenish-yellow color”; discovered in 1774

helium [He]—from Greek, helios, means Transition Metals “the sun”; first detected in 1895 on the sun Alkali Metals Metals Alkali Family Boron Carbon Family Nitrogen Family Oxygen Family Halogens Noble Gases A. Earth Metals Metals Earth A. Lanthanides hydrogen [H]—from Greek, hydros, Actinides means “water forming”; discovered in 1766; the first gas discovered Periodic Families Elements are grouped into columns, or phosphorous [P]—from Greek, families. All the elements in a family have phosphoros, means “light bearing”; similar properties. Some examples are discovered in 1669; some phosphorus described below: compounds glow in the dark

Alkali Metals—These elements are very polonium [Po]—discovered by Marie reactive. They especially react with Curie in 1898 and named for her native water, in some cases making large country, Poland; the rarest natural explosions. element

Halogens—Almost all of these elements silver [Ag]—symbol from Latin, argentum; occur naturally in pairs: F2, Cl2, Br2, I2. known to the Ancient World; the best conductor of heat and electricity Noble Gases—These elements are famous for being very stable. Since they tungsten [W]—from Swedish tung sten, don’t often react, scientists only means “heavy stone”; symbol from discovered them after the periodic table German wolfram means “wolf’s froth”; was made. metal with the highest melting point