383 results for: Elements

el·e·ment    Audio Help   /ˈɛləmənt/ Pronunciation Key - Show Spelled Pronunciation[el-uh-muhnt] Pronunciation Key - Show IPA Pronunciation

–noun

1.	a component or constituent of a whole or one of the parts into which a whole may be resolved by analysis: Bricks and mortar are elements of every masonry wall.

2.	Chemistry. one of a class of substances that cannot be separated into simpler substances by chemical means. See also chart under periodic table.

3.	a natural habitat, sphere of activity, environment, etc.: to be in one's element; Water is the element of fish.

4.	elements, a. atmospheric agencies or forces; weather: a ruddy complexion from exposure to the elements. b. the rudimentary principles of an art, science, etc.: the elements of grammar. c. the bread and wine of the Eucharistic service.

5.	any group of people singled out within a larger group by identifiable behavior patterns, common interests, ethnic similarities, etc.: He worried that the protest rally would attract the radical element.

6.	one of the substances, usually earth, water, air, and fire, formerly regarded as constituting the material universe.

7.	Mathematics. a. an infinitesimal part of a given quantity, similar in nature to it. b. an entity that satisfies all the conditions of belonging to a given set.

8.	Geometry. one of the points, lines, planes, or other geometrical forms, of which a figure is composed.

9.	Astronomy. any of the data required to define the precise nature of an orbit and to determine the position of a planet in the orbit at any given time.

10.	Electricity. an electric device with terminals for connection to other electrical devices.

11.	Radio. one of the electrodes in a vacuum tube.

12.	Astrology. any of the four triplicity groupings of signs: fire, earth, air, or water.

13.	Optics. any of the lenses or other components constituting an optical system.

14.	Grammar. any word, part of a word, or group of words that recurs in various contexts in a language with relatively constant meaning.

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[Origin: 1250–1300; ME (< AF) < L elementum one of the four elements, letter of the alphabet, first principle, rudiment]

—Synonyms Element, component, constituent, ingredient refer to units that are parts of whole or complete substances, systems, compounds, or mixtures. Element denotes a fundamental, ultimate part: the basic elements of matter; resolve the problem into its elements. Component and constituent refer to a part that goes into the making of a complete system or compound. Component often refers to one of a number of parts: a new component for the stereo system. Constituent suggests a necessary part of the whole: The constituents of a molecule of water are two atoms of hydrogen and one of oxygen. Ingredient is most frequently used in nonscientific contexts: the ingredients of a cake; the ingredients of a successful marriage.

The Columbia Electronic Encyclopedia Copyright © 2004, Columbia University Press.
Licensed from Columbia University Press

Overview

The term "transfermium" describes the elements with atomic numbers greater than 100. Fermium is element 100, so transfermium means "beyond fermium." The transfermium elements are grouped together for a number of reasons. First, they are all prepared artificially. None of them occur in the Earth's crust naturally (that anyone knows of). Second, they can be made with only the greatest difficulty. In fact, no more than a few atoms of some transfermium elements have been created so far. Third, very little is known about the transfermium elements. With only a few atoms to study, it is difficult to learn much about them.

Still, the transfermium elements are of great interest to chemists and physicists. They help answer questions about the periodic table. The periodic table is a chart that shows how chemical elements are related to each other. The transfermium elements are found at the very end of the periodic table. Scientists want to know if there is a limit to how heavy a chemical element can be. They also want to know what the properties of these very heavy elements will be like.

The chart below gives basic information about the transfermium elements. A discussion of the names and symbols in the chart follows in the next section.

Discovery of the elements

All transfermium elements are made in particle accelerators, or "atom smashers." A particle accelerator is a machine that makes very tiny particles, like protons or small atoms, move very fast. They often go nearly as fast as the speed of Light. Light travels about 300,000,000 meters per second (186,000 miles per second).

These fast moving particles are then made to smash into atoms. If they hit an atom just right, they will stick to the atom, making it heavier. For example, when fast moving neon atoms strike atoms of americium, the following reaction can occur:

The new element, dubnium (number 105), is produced.

This kind of experiment is easy to describe but very difficult to carry out. In fact, this research is carried out at only three laboratories in the world. One is the Joint Institute of Nuclear Research, in Dubna, Russia. The second is the Lawrence Berkeley Laboratory at the University of California at Berkeley in the United States. The third is the Institute for Heavy Ion Research in Darmstadt, Germany. All three laboratories use large particle accelerators that cost millions of dollars. Dozens of scientists from many different countries work on each team.

Credit for discovery of a transfermium element is extremely complicated. In most cases, no more than a handful of atoms is produced in an atom smasher. For example, the Dubna group first claimed to have found element 104 in 1964, but many scientists doubted this report. Five years later, American scientists also reported making element 104. This time, the evidence was better.

Naming the elements

One reason that scientists often argue over the discovery of an element is this: The group of scientists that discovers an element usually has the opportunity to suggest a name for it. For example, researchers at the Berkeley laboratory first discovered elements 97 and 98. They suggested naming those elements berkelium and californium, in honor of Berkeley, California, where the research was done.

The final decision about naming elements is made by a group called the International Union of Pure and Applied Chemistry (IUPAC). The decision can take a very long time. The IUPAC spent nearly 20 years trying to agree on names for elements 104, 105, and 106. Finally, in 1997, the IUPAC announced the official and final names for elements 101 through 109. Those names and their symbols are shown in the accompanying chart.

The names chosen by the IUPAC honor either great scientists or places of importance. The meaning of the names is as follows:

Mendelevium (Md): named after Russian chemist Dmitri Mendeleev (1834-1907), who developed the periodic law and the periodic table

Nobelium (No): named after Swedish inventor Alfred Nobel (1833-96), who provided funding for the Nobel Prizes when he died

Lawrencium (Lr): named after American physicist Ernest Orlando Lawrence (1901-58), who invented one of the first particle accelerators and for whom the Lawrence Berkeley Laboratory is named

Rutherfordium (Rf): named after British physicist Ernest Rutherford (1871-1937), who made many important discoveries about atoms and radioactivity

Dubnium (Db): named after Dubna, the city in Russia where the Joint Institute for Nuclear Research is located

Seaborgium (Sg): named after American chemist Glenn Seaborg (1912-), who has been involved in the discovery of ten elements

Bohrium (Bh): named after Danish physicist Niels Bohr (1885-1962), who helped develop the modern theory of the atom

Hassium (Hs): named after the German state in which the Institute for Heavy Ion Research is located

Meitnerium (Mt): named after Austrian physicist Use Meitner (1878-1968), who helped explain the process of nuclear fission (the splitting of atoms)

The IUPAC has not yet assigned names for elements 110 through 112. Discovery of those elements has been announced by the German team. But those discoveries have not yet been confirmed. Therefore, temporary names have been assigned. Those names come from the Latin words for the numbers 110, 111, and 112. They are ununnilium (Uun), unununium (Uuu), and ununbiium (Uub).

Properties of the elements

No one knows much about the properties of the transfermium elements. It isn't possible to see or touch or smell or taste any of these elements. There are often no more than a few dozen atoms to study.

In fact, it is quite amazing that scientists know much of anything about these elements. Yet, they do know a few things. In 1997, for example, the German team studied the properties of element 106, seaborgium, with only six atoms to work with! But they managed to watch how these atoms behaved as they slowly moved down a column of special material.

Of course, these elements have no uses.

Isotopes

Most transfermium elements have more than one isotope. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope.

The number of isotopes currently known for each element follows. The numbers may change as scientists discover new isotopes.

mendelevium: 13

nobelium: 11

lawrencium: 8

rutherfordium: 6

dubnium: 5

seaborgium: 3

bohrium: 2

hassium: 1

meitnerium: 1

All of the isotopes of the transfermium elements are radioactive. A radioactive isotope is one that breaks apart and gives off some form of radiation. In most cases, they have very short half lives. The half life of a radioactive isotope is the time it takes for half of a sample to break apart.

The half life of most transfermium isotopes is only a few seconds or less. The half life of dubnium-260, for example, is 1.6 seconds. That means that half of the atoms in a sample will break down in 1.6 seconds and change to some other element. Short half lives of the transfermium isotopes makes them hard to study. They tend to break down almost as soon as they are formed. Scientists have very little time to observe them.

Chemical Elements: From Carbon to Krypton
Copyright © 1999 by The Gale Group.
Published by The Gale Group. All rights reserved, including the right of reproduction in whole or in part in any form.

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