Compounds of strontium and halogens are common. Strontium chloride is the compound added to toothpaste to reduce pain. There are no major uses for strontium in the production of metal alloys. Strontium-90 is one of the most dangerous radioactive elements present in the fallout because it can accumulate in tissues. As you can see, high levels of Sr-90, in red, spread East across the mid-west from the source in Nevada. as a result of nuclear tests conducted in the Nevada desert in the 1950s. Here is a map of strontium-90 concentrations around the U.S. Nuclear fallout is when these contaminants are released into the atmosphere, where they then get spread across a region, and then begin to settle on the ground. Strontium-90 is a rare element that can be found in nature but it is a contaminant produced during malfunctions of nuclear power plants and nuclear bombs. Strontium-88 is the most abundant at 83%. Strontium-86 and -87 have abundances that range from 10 to 7%. Strontium-84 is least abundant, having a 0.6% abundance. Strontium on Earth is a mixture of four stable isotopes. Electronegativity: 0.95 (Pauling scale).The same reaction occurs for alkali metals, but they form much stronger, corrosive bases. Reactions with water form alkaline hydroxides and hydrogen gas. Strontium reacts vigorously in cold water. Therefore, they all commonly bond with other elements at a +2 oxidation state, although others may exist. All alkaline earth metals have this valence configuration, which is called divalent ( di– means 2). Strontium has 2 valence electrons, filling the 5s orbital. You may notice that all of these elements are found in groups 1 and 2. Only cesium, beryllium, magnesium, rubidium, calcium, sodium, potassium, and lithium have lower densities. It has one of the lowest densities of any metal and elements that are solid at room temperature. It vaporizes at 1377☌, which is similar to lithium. It melts at 777☌, which is similar to barium and cerium. Its thermal conductivity is about ten-times less than silver, which is the best conductor of heat. Strontium is also an intermediate conductor of heat similar to lead and cesium. Its electrical conductivity is about ten-times less than silver, which is the best conductor of electricity. Its electrical conductivity is similar to rubidium and chromium. Strontium is an intermediate conductor of electricity. It is highly reactive and so must be protected from air to prevent corrosion. The same trend is true for electronegativity. Ionization energy decreases down group 2, so strontium has an ionization energy intermediate to calcium and barium. Elements with higher ionization energies are generally more stable because they require more energy in the form of heat, for example, to release an electron. Ionization energy is the amount of energy required to remove an electron. For example, atomic radius increases down the group, so strontium atoms are larger than calcium but smaller than barium. This is related to its position on the periodic table in period 5, with 4 elements in higher periods and two elements below. There are trends down the group two elements, and the characteristics of strontium are somewhere in the middle. Strontium is named after the Scottish village, Strontian, where its mineral was discovered. basic or alkaline) when dissolved in water. They are called alkaline earth metals because their oxides have a high pH (i.e. They all have a similar appearance, electron configuration, and oxidation states. They include beryllium, magnesium, calcium, strontium, and barium, and radium. Strontium is not an essential element for humans but it has properties similar to calcium, so it is incorporated into growing bones.Īlkaline earth metals are found in group 2 of the periodic table. Strontium is used in fireworks, toothpaste, x-ray filters, and geology research. It is highly reactive and found on Earth combined with sulfate and carbonate minerals. It is soft, silvery-yellow, and metallic in appearance. In order to be neutral, an atom must have the same number of electrons and protons.Strontium is an alkaline earth metal. If a neutral atom has 10 protons, it must have 10 electrons. If a neutral atom has 2 protons, it must have 2 electrons. If a neutral atom has 1 proton, it must have 1 electron. In other words, a neutral atom must have exactly one electron for every proton. This means that the negative charge on an electron perfectly balances the positive charge on the proton. Negative and positive charges of equal magnitude cancel each other out. \)) are useful, because, as you can see, the mass of a proton and the mass of a neutron are almost exactly \(1\) in this unit system.
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