![]() ![]() One aluminum phosphate mineral is variscite, AlPO 4.2H 2O, which exhibits an apple green color and is popular as an ornamental stone. Aluminum with boron and fluorine form the oxide (borate) Jeremejevite. Aluminum with zinc forms the oxide mineral gahnite. Another oxide of aluminum is diaspore, AlO(OH).Īluminum along with magnesium form the oxide mineral spinel. Pure corundum is colorless, but the addition of a small impurity of chromic oxide can make the precious stone ruby (red) and the addition of titanium oxide can make sapphire (blue and other colors). Corundum and impure corundum called emery are used in making abrasive cloths and wheels. Other lithium aluminum silicates are spodumene, LiAlSi 2O 9 and petalite, LiAlSi 4O 10.Īluminum oxide, Al 2O 3, is called alumina and occurs in nature as the mineral corundum. The aluminum silicate kyanite forms blue crystals which can be of gem quality. A silicate with calcium, zoisite forms blue gems. A silicate with potassium, KAlSi 3O 8, forms the mineral microcline, which can be apple green to brown in color. One aluminum silicate, Al 2SiO 4 (F,OH) 2, forms the gem mineral topaz. Some aluminum silicates, like zunyite, contain fluorine and chlorine. Aluminum combines with other metals in many silicates, e.g., manganese in spessartine, Mn 3Al 2(SiO 4) 3. One aluminum silicate mineral is pyrophyllite, AlSi 2O 5(OH). It is a constituent of the class of silicates called feldspars, which are the most abundant minerals in the Earth's crust. ![]() When strongly heated it burns rapidly in air, and in the form of a fine dust is explosive.Īluminum is one of the big 8 elements in the Earth's crust, being the third most abundant element at about 8.1% by weight. Its drawback there is its tendency to oxidize at contacts, requiring the use of contacts coated with an antioxidant.Īluminum is a very active metal, a fact often disguised by the fact that it rapidly forms barrier oxide layers on exposed surfaces, inhibiting its interaction. It has high electrical conductivity, 80% of that of copper, and is used in place of copper in large electrical conductors. While much stronger than pure aluminum, this alloy is less resistant to corrosion and is often clad with pure aluminum.īecause of its lightness and strength, aluminum is used widely in aircraft construction. Duraluminum is formed from 94.3% aluminum, 4% copper, 0.5% manganese, 0.5% magnesium, and 0.7% silicon. The recycling of aluminum scrap metal saves over 90% of the energy required to separate aluminum from bauxite.Īluminum is only about one third as dense as iron, but some of its alloys, such as duraluminum are as strong as mild steel. The main drawback to its use is the large amount of energy necessary to refine it from its common ore, bauxite. Thus, the two electrons in the carbon 2 p orbitals have identical n, l, and m s quantum numbers and differ in their m l quantum number (in accord with the Pauli exclusion principle).Aluminum is an abundant, light, and strong metal which has found many uses. The orbitals are filled as described by Hund’s rule: the lowest-energy configuration for an atom with electrons within a set of degenerate orbitals is that having the maximum number of unpaired electrons. We now have a choice of filling one of the 2 p orbitals and pairing the electrons or of leaving the electrons unpaired in two different, but degenerate, p orbitals. The remaining two electrons occupy the 2 p subshell. Four of them fill the 1 s and 2 s orbitals. When drawing orbital diagrams, we include empty boxes to depict any empty orbitals in the same subshell that we are filling.Ĭarbon (atomic number 6) has six electrons. There are three degenerate 2 p orbitals ( m l = −1, 0, +1) and the electron can occupy any one of these p orbitals. Because any s subshell can contain only two electrons, the fifth electron must occupy the next energy level, which will be a 2 p orbital. ![]() The n = 1 shell is filled with two electrons and three electrons will occupy the n = 2 shell. The fourth electron fills the remaining space in the 2 s orbital.Īn atom of boron (atomic number 5) contains five electrons. Thus, the electron configuration and orbital diagram of lithium are:Īn atom of the alkaline earth metal beryllium, with an atomic number of 4, contains four protons in the nucleus and four electrons surrounding the nucleus.
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