3-7 Representitive Groups


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3-7 Representitive Groups

  1. 1. Warm-up <ul><li>Which of the following is not found in the nucleus of an atom? </li></ul><ul><ul><li>Protons </li></ul></ul><ul><ul><li>Neutron </li></ul></ul><ul><ul><li>Electron </li></ul></ul><ul><li>What is the mass of each of the subatomic particles? </li></ul><ul><ul><li>Proton – 1 amu </li></ul></ul><ul><ul><li>Neutron – 1 amu </li></ul></ul><ul><ul><li>Electron – 0 amu </li></ul></ul>
  2. 2. 3-7 Representative Groups <ul><li>Relate the number of valence electrons to the groups in the periodic table and to properties of elements in those groups. </li></ul><ul><li>Predict the reactivity of some elements based on their locations in the periodic table. </li></ul><ul><li>Identify some properties of common representative (A group) elements </li></ul>
  3. 3. Groups <ul><li>Alkali Metals </li></ul><ul><ul><li>Group 1 </li></ul></ul><ul><ul><li>1 valence electron </li></ul></ul><ul><ul><li>Extremely reactive </li></ul></ul><ul><ul><li>Found in nature only in compounds. </li></ul></ul><ul><ul><li>Reactivity increase from top to bottom. </li></ul></ul><ul><li>Alkaline Earth Metals </li></ul><ul><ul><li>Group 2 </li></ul></ul><ul><ul><li>Two valence electrons. </li></ul></ul><ul><ul><li>Higher melting points than group 1. </li></ul></ul><ul><ul><li>Lower reactivity than group 1. </li></ul></ul>
  4. 4. <ul><li>Boron Family - Group 13 </li></ul><ul><ul><li>3 valance electrons </li></ul></ul><ul><li>Carbon Family – Group 14 </li></ul><ul><ul><li>4 valance electrons </li></ul></ul><ul><li>Nitrogen Family – Group 15 </li></ul><ul><ul><li>5 valence electrons </li></ul></ul><ul><li>Oxygen Family – Group 16 </li></ul><ul><ul><li>6 valance electrons </li></ul></ul>
  5. 5. <ul><li>Halogens </li></ul><ul><ul><li>Group 17 </li></ul></ul><ul><ul><li>7 Valance electrons </li></ul></ul><ul><ul><li>Salt formers </li></ul></ul><ul><ul><li>Very reactive </li></ul></ul><ul><ul><li>Reactivity decreases top to bottom. </li></ul></ul><ul><li>Nobel Gases </li></ul><ul><ul><li>Group 18 </li></ul></ul><ul><ul><li>8 valance electrons </li></ul></ul><ul><ul><li>Very stable </li></ul></ul><ul><ul><li>Almost no compound form with Nobel gases </li></ul></ul><ul><ul><li>Colorless, odorless gases </li></ul></ul>
  6. 6. Element you might know <ul><li>Sodium </li></ul><ul><ul><li>Alkali metal </li></ul></ul><ul><ul><li>Found in table salt – sodium chloride </li></ul></ul><ul><li>Magnesium </li></ul><ul><ul><li>Alkali earth metal </li></ul></ul><ul><ul><li>Key to chlorophyll, which is need for plant to make food. </li></ul></ul><ul><ul><li>Used to make steel stronger, but lighter. </li></ul></ul><ul><li>Calcium </li></ul><ul><ul><li>Needed to keep strong bones and teeth </li></ul></ul><ul><ul><li>Main ingredient in chalk, toothpaste, and pearls. </li></ul></ul>
  7. 7. <ul><li>Aluminum </li></ul><ul><ul><li>Most abundant metal found in Earth’s crust. </li></ul></ul><ul><ul><li>Low re activity </li></ul></ul><ul><ul><li>Strong, lightweight, malleable and conductive. </li></ul></ul><ul><li>Carbon </li></ul><ul><ul><li>All living organisms are built on carbon-based compounds. </li></ul></ul><ul><li>Nitrogen </li></ul><ul><ul><li>About 78% of earth’s atmosphere is nitrogen. </li></ul></ul><ul><ul><li>Used in fertilizers </li></ul></ul>
  8. 8. <ul><li>Oxygen </li></ul><ul><ul><li>Most abundant element in earth’s crust. </li></ul></ul><ul><ul><li>Oxygen is highly flammable. </li></ul></ul><ul><ul><li>Ozone is another form of oxygen that is found in the upper atmosphere, which absorbs harmful radiation. </li></ul></ul><ul><li>Fluorine </li></ul><ul><ul><li>Used in toothpaste to help prevent tooth decay. </li></ul></ul><ul><ul><li>Used in nonstick coatings </li></ul></ul>
  9. 9. <ul><li>Chlorine </li></ul><ul><ul><li>Used chorine bleach </li></ul></ul><ul><ul><li>Added to city water supplies and pools to kill bacteria. </li></ul></ul><ul><li>Argon </li></ul><ul><ul><li>Highly unreactive element </li></ul></ul><ul><ul><li>Used in light bulbs to increase lifetime. </li></ul></ul><ul><ul><li>Used in “neon” lights – lavender color. </li></ul></ul>
  10. 10. Valence Electrons <ul><li>Valence electrons are electrons that occupy the outer most energy level while still being in the ground state. </li></ul><ul><ul><li>Outermost energy level corresponds to the highest energy level. </li></ul></ul><ul><li>Electrons play a key role in chemistry. </li></ul><ul><ul><li>Electrons are on the outside of the atom. </li></ul></ul><ul><ul><li>Electrons “touch” other electrons. </li></ul></ul><ul><li>Electrons give elements their chemical and physical properties. </li></ul>
  11. 11. Electron Dot Structure <ul><li>The electrons on the inner shell play a minor role in chemical properties. </li></ul><ul><li>Electron in the outside shell (energy level) play the major role. </li></ul><ul><li>Model of the atom that show only the valence electrons. </li></ul>
  12. 12. 3-7 Summary <ul><li>What do elements in the same group have in common? </li></ul><ul><ul><li>Similar properties </li></ul></ul><ul><ul><li>Same number of valence electrons. </li></ul></ul><ul><li>How many valence electrons to group 1 have? What are properties? Name? </li></ul><ul><ul><li>Alkali metals </li></ul></ul><ul><ul><li>Extremely reactive </li></ul></ul><ul><ul><li>1 valence electron </li></ul></ul><ul><ul><li>Reactivity increases top to bottom. </li></ul></ul>
  13. 13. 3-8 Summary (Cont.) <ul><li>How can one tell the difference between group 1 and 2? </li></ul><ul><ul><li>Reactivity with water, Alkali earth metals are less reactive. </li></ul></ul><ul><li>What do halogens have in common? </li></ul><ul><ul><li>7 valence electron. </li></ul></ul><ul><ul><li>Very reactive nonmetals </li></ul></ul><ul><li>Describe the characteristics of Nobel gases. </li></ul><ul><ul><li>Colorless, odorless, completely unreactive gases. </li></ul></ul>