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Chemistry and the Elements

Properties of Matter10. Metals: Found on left side of periodic table.Nonmetals: Found on the right side of periodic table.Semimetals: Form a zigzag line at the boundary between metals and nonmetals. . How were some of the first elements discovered?. Ten elements were discovered before recorded

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Chemistry and the Elements

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    29. What is the mass of a mol of 1H atoms? 1.67x10-24 g/atom x 6.01 x 1023 atoms = 10x10-1g The mass of a mol of hydrogen atoms is 1 g What is the mass of a 35Cl atom? 35Cl = 17p+18n 17(1.67x10-24g) + 18(1.67x10-24g) 35Cl 35(1.67x10-24g) = 58.5 x 10-24g What is the mass of a mol of 35Cl atoms? 35Cl 35(1.67x10-24g) x 6.01x 1023 = 35 What is the mass of a 37Cl atom? 37Cl = 17p+20n 17(1.67x10-24g) + 20(1.67x10-24g) 37Cl 37(1.67x10-24g) = 61.8 x 10-24g What is the mass of a mol of 37Cl atoms? 37Cl 37(1.67x10-24g) x 6.01x 1023 = 37 Previously we defined: Atomic Weight as the sum of the number of protons and neutrons in the nucleus Let us now define the Gram Atomic Weight as the weight in grams of a mol of an element

    30. Since the mass of a neutron and proton are nearly identical and since each element of the perioic table differs only in the number of protons and neutrons in the nucleus, an element with X number of neutrons and Y protons in the nuclues will have an atomic weight of X+Y, and a mol of the element will consist of X+Y grams since: X+Y (1.67x10-24 g x 6.01 x 1023 atoms/mol) = X+Yg Atomic Weight is defined as X+Y Gram Atomic Weight is defined as (X+Y)g.

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