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.

Darmstadtium

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Darmstadtium, symbol Ds, chemical element with atomic number 110. It is produced artificially by nuclear fusion (in which an element with larger atoms is produced by fusing together smaller atoms from other elements). Each darmstadtium atom has a very large nucleus, or central mass, containing positively charged particles called protons and neutral particles called neutrons. The large number of particles in the nucleus makes the atom unstable and causes the atom to split apart into smaller components soon after it is created. Darmstadtium was first discovered in 1994 by scientists at the Heavy-Ion Research Laboratory in Darmstadt, Germany. The scientists named darmstadtium after the place of its discovery.

Darmstadtium has the atomic number 110, which means that each Ds atom contains 110 protons in the nucleus. Scientists have created a number of isotopes of darmstadtium. Isotopes are forms of the element that contain different numbers of neutrons in the nucleus. For example, Ds-269 contains 110 protons and 159 neutrons (110 protons + 159 neutrons = atomic mass 269). Similarly, Ds-271 contains 110 protons and 161 neutrons.

Darmstadtium was created by nuclear fusion of the smaller elements lead (Pb) and nickel (Ni). Because the darmstadtium nucleus contains so many particles, darmstadtium is unstable and undergoes spontaneous fission, a process in which the atom breaks into smaller “daughter” components. When the atom splits, it releases energy in the form of electromagnetic waves and electrically charged bits of matter. This energy is known as radiation (see Radioactivity).

Darmstadtium belongs to Group 10 (VIIIb) on the periodic table, which also contains the naturally occurring elements nickel (Ni), palladium (Pd), and platinum (Pt). Nickel, palladium, and platinum are all whitish-silver, shiny metals that are both malleable (can be shaped by hammering) and ductile (can be drawn into wire). Under normal conditions, these metals are resistant to corrosion, each forms a complex with four chloride ions, and all react with oxygen when heated. Because elements in the same group, or column, on the periodic table often share similar properties (a pattern known as the periodic law), scientists expect darmstadtium to share properties with other Group 10 elements. However, because of the limited amount of darmstadtium that can be produced and its extremely short lifespan, scientists have been unable to determine chemical properties of this highly unstable element.