Squares for each element are distorted in proportion to the numerical value of the abundance. A cartogram depicting the abundance of elements in the earth's crust. This shows up best using the "Bar chart" option on the chart. Notice the "sawtooth" effect where elements with even atomic numbers tend to be more strongly represented than those with odd atomic numbers. The alkaline-earth elements are highly metallic and are good conductors of electricity. The elements are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). The chart above shows the log of the abundance (on a parts per billion scale) of the elements by atom number in our sun. Alkaline-earth metal, any of the six chemical elements that comprise Group 2 of the periodic table. Image showing periodicity of the logarithm of the abundance (by atom rather than weight) in the sun of the chemical elements as a heat map on a periodic table grid. Image showing periodicity of the logarithm of the abundance in the earth's crust of the chemical elements as a heat map on a periodic table grid. Use the links in the location column for definitions, literature sources, and visual representations in many different styles (one of which is shown below) Location Local concentrations of any element can vary from those given here an orders of magnitude or so and values in various literature sources for less common elements do seem to vary considerably.Ībundances for calcium in a number of different environments. Values for abundances are difficult to determine with certainty, so all values should be treated with some caution, especially so for the less common elements. In this table of abundances, values are given in units of ppb (parts per billion 1 billion = 10 9), both in terms of weight and in terms of numbers of atoms. Abundances of calcium in various environments Apatite is calcium fluorophosphate or chlorophosphate. It occurs as limestone (CaCO 3), gypsum (CaSO 4.2H 2O), and fluorite (CaF 2). Calcium is fifth in abundance in the earth's crust, of which it forms more than 3%. Calcium metal is never found as the free metal in nature. (2012, December 18) Valence Electrons and the Periodic Table. If the valence shell of an element is full, such as with a noble gas, then the element does not want to gain or lose an electron.įor example, alkali metals, which all have a valency of 1, want to lose that one electron and are likely to form ionic bonds (such as in the case of NaCl, or table salt) with a Group 17 element, which has a valency of 7 and wants to gain that one electron from the alkali metal (Group 1 element) to form a stable valency of 8.įor more on valence electrons and how they're related to the periodic table, I strongly recommend this video:Ĭitations: Tyler Dewitt. They determine how "willing" the elements are to bond with each other to form new compounds. Valence electrons are responsible for the reactivity of an element. You can easily determine the number of valence electrons an atom can have by looking at its Group in the periodic table.įor example, atoms in Groups 1 and 2 have 1 and 2 valence electrons, respectively.Ītoms in Groups 13 and 18 have 3 and 8 valence electrons, respectively. Valence electrons are the electrons present in the outermost shell of an atom. To form a covalent bond, one electron from the halogen and one electron from another atom form a shared pair.įor example, in #"H–F"#, the dash represents a shared pair of valence electrons, one from #"H"# and one from #"F"#. To form an ionic bond, a halogen atom can remove an electron from another atom in order to form an anion (e.g., #"F"^"-", "Cl"^"-"#, etc.). They have one less electron configuration than a noble gas, so they require only one additional valence electron gain an octet. The most reactive nonmetals are the halogens, e.g., #"F"# and #"Cl"#. A second grouping includes calcium (Ca), strontium (Sr), and barium (Ba), which also are shiny, good conductors of heat and electricity, and have chemical. Nonmetals tend to attract additional valence electrons to form either ionic or covalent bonds. They need to lose only one or two valence electrons to form positive ions with a noble gas configuration. In the Modern Periodic Table, calcium (atomic number 20) is surrounded by elements with atomic numbers 12, 19, 21 and 38. The most reactive metals are those from Groups 1 and 2. The usual charge of an element is common to its group. Generally, elements in Groups 1, 2, and 13 to 17 tend to react to form a closed shell with a noble gas electron configuration ending in #ns^2 np^6#. How to Find the Charge of an Element There are four ways to find the charge of an element: Use the periodic table. Elements whose atoms have the same number of valence electrons are grouped together in the Periodic Table.
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