Periodic Table Gallery

An exciting time for chemistry

Two new elements, flerovium Fl and livermoreium Lv have been approved for entry in the Periodic Table of the Elements! They were formerly known by blander names—ununquadium and ununhexium. In honor of the event, I assembled a gallery of periodic tables, but let me tell you more about the table first.

The chemical elements are arranged from top to bottom, in order of lowest to highest atomic number. (Atomic number is the same as the number of protons.) There are 118 elements. 98 are naturally occurring, and 14 occur naturally in decay chains of those 98, up to and including californium. The remaining six elements are lab synthesized.

timmurtaugh via Flickr

Periodic Tattoo

Why is it periodic?

Table rows are “periods” and table columns are “groups.” Some groups have specific names, e.g. the noble gases, occupying the last column on the right. Some rows do too, such as the lanthanides and actinides on the bottom two rows.

The table is also periodic because its inventor, Dmitri Mendeleev, intended for it to be updated periodically, as new elements are found. So Mendeleev’s design had a dual use: for describing how the elements relate to each other, as well as for inferring the properties of new and not yet found elements.

One scientific concept to rebuild civilization

The children’s Periodic Table on the U.S. EIA website has the basics. It links to Los Alamos National Lab’s (LANL) Periodic Table.

Photo of Los Alamos National Labs chemist with period table

Actinides at LANL

Here is a great quote from a recent LANL news story by David Hobart, Actinide Analytical Chemistry, History of the periodic table…and my history with it:

As the legendary physicist Richard Feynman put it, “If some universal catastrophe was to engulf the world and humankind could retain only one scientific concept to rebuild civilization, what would it be? The chemist’s answer is almost invariably the Periodic Table of the Elements.


Published in: on March 24, 2012 at 9:02 am  Comments (8)  
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Rare-Earth Metals, China Update 1

A better title would have been Postcard: People’s Republic of China, except for the fact that I’m in Arizona. Let’s begin with the impending global rare-earth metals shortage.

What are rare-earth metals?

Possible shortages in rare-earth metals seems arcane. What are they? Depending on who you ask, they are 15 to 30 elements with the following common properties: A silvery or grey appearance, high luster that is quick to tarnish in air and very high electrical conductivity. They are not all that rare, but earned their name from the tedious process by which they were extracted prior to advancements in metallurgy in the 1950’s.

Periodic table

Lanthanide series and a few more: The 17 Rare-earth Elements

Here is a most beautiful Periodic Table of the Elements by Perioden System. If you like the Periodic Table, I highly recommend having a look at their interactive version, on Perioden System’s home site. Super-high resolution downloads are available free.

The 17 elements that are universally considered rare-earth elements are also known as the Lanthanides. The name is pleasingly appropriate, as it is derived from the Greek lanthanon, meaning I am hidden. They appear on the bottom drop-down of the chart, numbers 57 Lanthanum, through 71 Lutetium. Elements Scandium and Yttrium comprise the rest of the rare-earth metals. Several members of the second series, the Actinides, are also classified rare-earth by some, including Thorium and Uranium.

Important! Precious metals, which are refined from the elements Gold, Platinum, Palladium, Silver, Rhodium and Iridium are NOT in the same group as the Rare-Earth elements. This confusion is common. Referring to the Periodic Table will clarify, as precious metals have atomic numbers 45-47 and 77-79.

China now mines 95% of the world’s rare-earth metal

Physics Today Online

Rare-Earth Metals Shortage

Physics Today (May 2010) reports new concerns over China’s dominance of rare-earth mining. This presents a risk exposure to the People’s Republic of China, as the U.S.A. and the rest of the world have been highly dependent on China as a source of rare-earth metals for decades.

Demand is expected to increase as green technologies gain more acceptance and use. Special batteries use rare-earth metals. Hybrid car motor construction requires Dysprosium, element 66. All of the heavy rare-earth metals such as Dysprosium are mined in China. Heavy refers to heavy nuclei, which simply means a larger number on the periodic table. In general, the heavier nuclei rare-earth elements are the most sought after.

According to the Physics Today article, concentration of both rare earth metals and rare earth mining activity has shifted the world’s rare earth knowledge base, from the U.S.A., South America and Africa to China. Over 80% of the world’s material scientists, geologists and experts in rare-earth metals reside in China. Consequences of this localization are dramatic. For example, the division of General Motors which deals with miniaturized magnet research shut down its US office and moved the entire staff to China.

USGS summary of RE element mining activity

Rare-earth oxide production per year*

On September 1, 2009, China announced plans to cut its rare earth mining quota to 35,000 tons per year in 2010-2015 to conserve scarce resources and protect the environment. This isn’t necessarily a play for monopoly power and hegemony, as there is a limited supply of natural resources. Illegal rare earth mines are common in rural China and release toxic wastes into the general water supply, presenting further environmental concerns for China.

* Chart of global rare-earth resources courtesy of Wikipedia and the U.S. government