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Atoms and Elements 1. There are billions of materials in our universe. 2. Those materials are made up from about 100 elements only. An element is a substance that is made from one kind of atom only. It cannot be broken down into simpler substances. atom An element atom An element A substance made from only one type of atom is a MOLECULE, and because all the atoms are the same, it is still an element. Molecules can also be substances made from more than one element. (These are also called compounds) atom A molecule made up of 2 different elements atom A molecule made up of 7 different elements A molecule that is a compound can be broken down into elements An element An element A molecule made up of 3 different elements An element Molecules • A molecule can be made from the same type of atom, or two or more different types of atoms ( a compound) • These can be broken down into individual elements. Chlorine Cl2 Methane CH4 Remember, all compounds are molecules but not all molecules are compounds Chemical formulas • These are used to represent molecules and indicate the type and number of elements that make up the molecule. Rules for chemical symbols in the periodic table: 1. The symbol is usually the first one or two letters of the name. 2. Sometimes the old (Latin) name is used . 3. The first letter of a symbol is always a capital letter. 4. The second letter of a symbol is always a small letter. 5. Every element has a different symbol. Numbers are used to represent how many of each element are present in the formula. • The numbers are written to the right of the element as a subscript (smaller and lower down) H2O • This tells us there are 2 atoms of hydrogen and only 1 atom of oxygen. What is a molecule? A) Atoms separated by tiny spaces B) Two or more atoms bonded together C) Only ever made of the same type of atom. D) Something that must always contain carbon What is a molecule? A) Atoms separated by tiny spaces B) Two or more atoms bonded together C) Only ever made of the same type of atom. D) Something that must always contain carbon How many of each atom are in the following formulas. • HCl • Cl2 • CO2 • CH4 How many of each atom are in the following formulas. • HCl 1 hydrogen and 1 chlorine • Cl2 • CO2 2 chlorine 1 carbon 2 oxygen • CH4 1 carbon 4 hydrogen Now look in your periodic table and find name that corresponds to the following symbol: Fe …….. Mg ……….. Ag ……….. K ……….. C ………… Ca ……. Na ………. N ……… Ne …….. Pb ………. Now look in your periodic table and find the symbols of the following elements, then find out if it is a metal or a nonmetal: Copper Cu Iron …Fe Magnesium …Mg Chlorine …Cl Carbon ……C Sodium …Na Lead …Pb Gold …Au Calcium …Ca Fluorine …F Now look in your periodic table and find if each is a metal or a non-metal: Copper ………….. Iron …………….. Magnesium …………….. Chlorine …………….. Carbon …………….. Sodium …………….. Lead …………….. Gold …………….. Calcium ………… Fluorine ………….. Now look in your periodic table and find out if each is a metal or a non-metal: Copper …metal Iron …metal Magnesium …metal Chlorine …non-metal Carbon …non-metal Sodium …metal Lead …metal Gold …metal Calcium …metal Fluorine …nonmetal