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Chapter 5 The Periodic Table
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Periodic Table Info
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Periodic Table Development Dimitri Mendeleev (1834 – 1907) Arranged the elements by increasing ATOMIC MASS Produced the first PERIODIC TABLE – 1871 The table placed elements with similar properties in the same column Kept “holes” for undiscovered elements, and predicted the properties in advance
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Mendeleev’s Periodic Table
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Predicting Properties
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New Periodic Table H. G. Moseley (1887-1915) Rearranged the elements by ATOMIC NUMBER This is the MODERN PERIODIC TABLE
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atomic number symbol name average atomic mass electron configuration What’s on the Periodic Table?
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GROUP: vertical column (family) similar chemical properites PEROID: horizontal row same filled energy levels Reading the Periodic Table
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Period Group 1 2 3 4 5 6 7
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Periodic Table Groups
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Properties of Metals 1.shiny (luster) 2.conductors of heat and electricity 3.Reactive with acids 4.ductile –can be stretched into a wire 5. malleable –can be hammered or rolled into sheets
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Properties of Nonmetals 1.Dull and brittle 2.poor conductors of heat and electricity 3.Does not react with acids 4.usually gases at room temp.
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PERIODIC LAW When elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic (repeating) pattern. Which means: there are patterns across the periodic table called periodic trends
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Atomic Radius half the distance from center-center of 2 like atoms
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Atomic Radii DOWN a Group ↓As you go down a group another energy level is added, the atom size gets larger
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Na Atomic Radius: down group P P P X X X P X P X P X P P P P P X X X X X X P
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K P P P X X X P X P X P X P P P P P X X X X X P X X X X X X X X X
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Atomic Radii DOWN a Group ↓DOWN THE GROUP ATOMIC RADIUS INCREASES more energy levels, the larger the size of the atom
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Atomic Radii ACROSS a Period → Each atom gains one proton and one electron in the same energy level →Each added electron is the same distance from the nucleus →The positive charge increases and exerts a greater force on the electrons thereby pulling it closer to the nucleus
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REMEMBER! PROTONS are bigger and stronger! electrons are smaller and weaker! P ++ - - e
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Atomic Radius: across period P P P X X X P X P X P X P P P P P X X X X X
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Atomic Radii ACROSS a Period →ACROSS THE PERIOD ATOMIC RADIUS DECREASES stronger attraction of protons, easier to hold on to the electrons
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amount of energy needed to remove an electron from an atom Ion: an atom that has gained or lost electrons if you lose an electron… if you gain an electron… Ionization Energy BECOMES POSITIVE! BECOMES NEGATIVE!
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Ionization Energy DOWN a Group ↓As you go down a group atoms become larger, electrons are farther from the nucleus and more easily removed
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Ionization Energy DOWN a Group ↓DOWN THE GROUP IONIZATION ENERGY DECREASES greater distance from the nucleus, the easier to lose an electron (less energy needed)
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Ionization Energy ACROSS a Period →As atomic radius decreases there is a greater attraction between protons and electrons. →The stronger the attraction, the more energy needed to remove an electron. →The more electrons present, the more energy required to remove them all to become STABLE
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Ionization Energy ACROSS a Period →ACROSS THE PERIOD IONIZATION ENERGY INCREASES more electrons on an energy level, more energy required to remove them all
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It is a “tug of war” between the two atoms of a bond Electronegativity H F : : : Which is the more electronegative element?... tendency for an atom to attract electrons
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Electronegativity ACROSS the Period →As you go across a period atomic radius decreases because there is a greater attraction between protons and electrons →Metals do not attract electrons. →Non-metals do attract electrons.
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Electronegativity ACROSS the Period →ACROSS THE PERIOD ELECTRONEGATIVITY INCREASES stronger the attraction, the easier to add more electrons
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Electronegativity DOWN the Group ↓The larger the atom, the less likely it is to accept more electrons.
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Electronegativity DOWN the Group ↓DOWN THE GROUP ELECTRONEGATIVITY DECREASES farther the distance from the nucleus, more difficult to attract electrons
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PUT IT ALL TOGETHER!
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Reactivity of Alkali Metals
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Where are the most reactive metals?
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Where are the most reactive nonmetals?
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Activity Series of the Elements
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1.Why is sodium not used for silverware? It is highly reactive and reacts with water.
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It does not react with oxygen or water and therefore does not readily break down.
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3. Why is food canned in containers made from steel coated with a thin layer of tin? Steel makes a strong container and the tin lining does not react with the contents.
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4. Why are cars painted? To prevent the iron from rusting by being exposed to oxygen in air.
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