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If an atom has more electrons than protons, then it has an overall negative charge and is called a negative ion (or anion). Conversely, if it has more protons than electrons, it has a positive charge and is called a positive ion (or cation). The electrons of an atom are attracted to the protons in an atomic nucleus by the electromagnetic force.
A fast-neutron reactor, meaning one with little or no neutron moderator and hence utilising fast neutrons, can be configured as a breeder reactor, producing more fissile material than it consumes, using fertile material in a blanket around the core, or contained in special fuel rods.
[50] [51] For cold-atom applications requiring tunable interactions, 85 Rb is preferred for its rich Feshbach spectrum. [ 52 ] Rubidium has been used for polarizing 3 He , producing volumes of magnetized 3 He gas, with the nuclear spins aligned rather than random.
Copper is a chemical element with symbol Cu and atomic number 29, known for its high thermal and electrical conductivity.
Pure water is an example of a chemical substance, with a constant composition of two hydrogen atoms bonded to a single oxygen atom (i.e. H 2 O). The atomic ratio of hydrogen to oxygen is always 2:1 in every molecule of water. Pure water will tend to boil near 100 °C (212 °F), an example of one of the characteristic properties that define it.
At room temperature, hydrogen bromide is a colourless gas, like all the hydrogen halides apart from hydrogen fluoride, since hydrogen cannot form strong hydrogen bonds to the large and only mildly electronegative bromine atom; however, weak hydrogen bonding is present in solid crystalline hydrogen bromide at low temperatures, similar to the ...
In the simplest case, the cation is a metal atom and the anion is a nonmetal atom, but these ions can be of a more complicated nature, e.g. molecular ions like NH 4 + or SO 4 2−. At normal temperatures and pressures, ionic bonding mostly creates solids (or occasionally liquids) without separate identifiable molecules, but the vaporization ...
The rationale of crystal geometry to atom solubility prediction is summarized in the Hume-Rothery rules and Pauling's rules. Substitutional solid solution strengthening occurs when the solute atom is large enough that it can replace solvent atoms in their lattice positions. Some alloying elements are only soluble in small amounts, whereas some ...