Matter & Energy


Matter is composed of atoms or groups of atoms called molecules. The arrangement of particles in a material depends on the physical state of the substance. In a solid, particles form a compact structure that resists flow. Particles in a liquid have more energy than those in a solid. They can flow past one another, but they remain close. Particles in a gas have the most energy. They move rapidly and are separated from one another by relatively large distances.

Ununquadium

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Element 114, also called ununquadium (Uuq), chemical element with atomic number 114. Each atom of the element has a nucleus, or central core, containing positively charged particles called protons and neutral particles called neutrons (see Atom). The number of protons in the nucleus of an atom of any element determines the element’s atomic number. Thus the nucleus of an atom of ununquadium contains 114 protons. The element is not found in nature but can be produced artificially by nuclear fusion (process in which a chemical element with larger atoms is produced by fusing together two smaller atoms of other elements). Atoms of ununquadium quickly decay into atoms of elements containing fewer protons and neutrons.

Ununquadium is a temporary name assigned according to a system that uses Latin prefixes for the atomic number (un = 1, quad = 4), followed by the suffix -ium. The International Union of Pure and Applied Chemistry will approve a permanent name for element 114 after its discovery has been confirmed.

Ununquadium belongs to Group 14 (or IVa), a column of the periodic table that also contains naturally occurring elements such as tin (Sn) and lead (Pb). Because elements in the same group of the periodic table often share similar properties (a pattern known as the periodic law), scientists expect ununquadium’s properties to resemble those of tin and lead. Scientists have been unable to examine ununquadium’s chemical properties, however, because of the limited amount and short life span of the isotope of ununquadium that has been produced. Isotopes are different versions of a single element that all contain the same number of protons but contain differing numbers of neutrons.

Because the ununquadium nucleus contains so many particles, ununquadium is unstable and undergoes spontaneous fission, a process in which the atom breaks into smaller “daughter” components. The super-heavy ununquadium-289 isotope produced at Dubna took about 30 seconds to decay; all other known atoms with similar numbers of particles packed into their nuclei decay in a fraction of a second. Scientists have predicted an island of stability centered around an atom that contains 114 protons and 184 neutrons. The atom produced at Dubna contained exactly the desired number of protons, and nearly the desired number of neutrons. Its relatively long decay time lends credibility to the stability predictions. Scientists at Dubna later produced a second isotope, ununquadium-287. As expected, this isotope, containing two fewer neutrons than ununquadium-289 and so positioned further from the theoretical island of stability, decayed in a fraction of second. Future research will probably focus on reaching the island of stability by producing ununquadium-298, the isotope of the element containing 184 neutrons. This isotope might have a decay time measured in hours or even days, far longer than any other artificially produced element.