Chapter 5-The Periodic Table

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1 Chapter 5-The Periodic Table Organizing the elements --> Placement of elements in a table links the atomic structure of the elements and their properties Search for order --> In 1750 there were only 17 known elements > Antoine Lavoisier grouped all elements into 4 groups (metals, non-metals, gases & earths) Many attempts were made to classify elements over the next 80 years 1

Dmitri Mendeleyev, Russian chemist & teacher --> 1860 -arranged elements into rows according to increasing atomic mass.

2 Dmitri Mendeleyev, Russian chemist & teacher --> arranged elements into rows according to increasing atomic mass. Elements were arranged in columns, based on a set of properties that repeat from row to row. Not the first or last attempt at arranging elements in a table, but the best to describe how properties were related to location of the element on the table 2

3 Mendeleyev s table was not complete (many elements not yet discovered) - but he left spaces for elements to come. His predictions of the properties of new elements were incredibly accurate. Chemists use the Periodic Table to explain chemical behavior of groups of elements. 3

4 The Modern Periodic Table Mendeleyev s table was developed before the discovery of protons. The Periodic Law --> elements arranged by increasing atomic number (number of protons). Periods --> each row in the Periodic Table Elements become less metallic in their properties from left to right 4

5 Groups --> each column in the Periodic Table **Elements in a group have similar electron configurations** **Electron configurations determine chemical properties** Elements in the same group have similar chemical properties, but differences in reactivity. 5

Atomic Mass --> dependent upon the masses and distribution of the elements isotopes in nature atomic mass units (amu) --> originally assigned to the carbon-12 atom (6 protons and 6

6 Atomic Mass --> dependent upon the masses and distribution of the elements isotopes in nature atomic mass units (amu) --> originally assigned to the carbon-12 atom (6 protons and 6 neutrons) --> amu = 1/12 the mass of a carbon-12 atom. weighted average --> the atomic mass of an element is determined by adding up the contribution from each isotope of that element 6

Classes of Elements --> metals, nonmetals, & metalloids Metals --> located on the left side of the Periodic Table and includes the majority of elements properties of metals include: * good conductors

7 Classes of Elements --> metals, nonmetals, & metalloids Metals --> located on the left side of the Periodic Table and includes the majority of elements properties of metals include: * good conductors of electric current & heat * solids at room temperature (except mercury) * most are malleable and ductile (can be extruded) * some are reactive, some are not * Francium (lower left) is the most reactive metal Mg Na Ca 7

8 Transition metals --> in groups 3-12 * form a bridge between elements on the left and right sides of the Periodic Table * includes the lanthanide and actinide series Fe Zn 8

9 1 H Hydrogen 3 4 Li Na K Be Lithium Beryllium Mg Sodium Magnesium Ca Potassium Calcium Sc Ti V Cr Mn Fe Co Ni Cu Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Zn B Al Ga C Si Ge N P As O F Cl S Se Br 2 He Helium Ne Boron Carbon Nitrogen Oxygen Fluorine Neon Ar Aluminium Silicon Phosphorus Sulfur Chlorine Argon Kr Gallium Germanium Arsenic Selenium Bromine Krypton Rb Sr Rubidium Strontium Y Zr Nb Mo Tc Ru Rh Pd Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Ag Cd In Sn Sb Te I Xe Cs Ba Cesium Barium La Hf Ta W Re Os Lanthanum Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury Ir Pt Au Hg Tl Pb Bi Po At Rn Thallium Lead Bismuth Polonium Astatine Radon Fr Ra Francium Radium Ac Rf Db Sg Bh Hs Mt Actinium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Cf Th Pa U Np Pu Am Cm Bk Es Fm Md No Lr Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium 9

10 Nonmetals --> vary in physical & chemical properties C H Properties: * poor conductors * low boiling point (many are gases at room temp.) * solid nonmetals at room temperature are brittle * fluorine is the most reactive nonmetal O S P N Br 10

11 Metalloids --> properties fall between metals & nonmetals Si * Conductivity varies with temperature * Pure silicon (Si) and germanium (Ge) are good insulators at low temperatures and good conductors at high temps Ge 11

12 Groups in the Periodic Table *Valence electrons --> located in the highest occupied energy level of an atom * These are the electrons that are involved in chemical reactions * Elements in a group have similar properties because they have the same number of valence electrons * Properties are not identical because the valence electrons are in different energy levels 12

13 Valence Electrons and Ion Formation Stable Octet Rule: The most stable electron arrangement is to have 8 electrons in the outermost energy level for all elements (except Hydrogen and Helium, which are most stable with 2 electrons in their outermost energy level) Atoms will lose or gain electrons to achieve a stable octet. The number of electrons they lose/gain depends on the number of valence electrons they have. What is the # of valence electrons for the following: Lithium Sodium Potassium 13

14 Members of group 1A can either gain 7 electrons to reach a stable octet or lose 1 - and they tend to always do what requires gaining/losing the least - so they will lose 1 electron. What kind of ion is formed by losing 1 electron? +1 ion 14

15 What is the # of valence electrons for the following: Fluorine Chlorine Bromine Which group do they belong to? Members of group tend to gain 1 electron to reach a stable octet. What kind of ion is formed by gaining 1 electron? -1 ion 15

16 Groups tend to form the following ions: Group 1A = +1 ion Group 2A = +2 ions Group 3A = +3 ions Group 4A = +/-4 ions Group 5A = -3 ions Group 6A = -2 ions Group 7A = -1 ions Group 8A = already have stable octet, rarely form ions We will worry about down in the valley later!! 16

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18 Alkalai Metals (Group 1A) * Have 1 valence electron, form a +1 ion. * Are so reactive they are found only in compounds in nature * Reactivity increases from top to bottom of the group * Sodium & potassium are so reactive with oxygen and water they are stored in oil. * Cesium reacts with water as low as C 18

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Alkaline Earth Metals (Group 2A) * 2 valence electrons, form a +2 ion * harder than metals in group 1A * Differences in reactivity in this group are shown by the way they react with water.

20 Alkaline Earth Metals (Group 2A) * 2 valence electrons, form a +2 ion * harder than metals in group 1A * Differences in reactivity in this group are shown by the way they react with water. * Magnesium-in the center of chloryphyll is very strong yet has much less mass than steel - used in transportation industry * Calcium-essential for strong teeth and bones; contained in chalk, limestone, coral & pearls 20

21 Boron Family (Group 3A) * 3 valence electrons, form +3 ions * Boron is a metalloid * A compound of boron, silicon & oxygen is used in glass that can undergo rapid temperature change used to make cookware & laboratory glassware. * Aluminum- the most abundant metal in the earth s surface; Found in a compound with oxygen called bauxite; Strong, lightweight, malleable & a good conductor; More than 10% of the aluminum produced is used for packaging; Recycled aluminum costs only 5% compared to extracting from bauxite. 21

Carbon Family (Group 4A) * 4 valence electrons, form either +4 or -4 ions * Carbon is a nonmetal found in most compounds in your body (except water) and in all

22 Carbon Family (Group 4A) * 4 valence electrons, form either +4 or -4 ions * Carbon is a nonmetal found in most compounds in your body (except water) and in all cells of the body * This group also contains 2 metalloids & 2 metals * Silicon-second most abundant element on earth -silicon dioxide found in quartz, sand & glass 22

Nitrogen Family (Group 5A) * 5 valence electrons, forms -3 ions * Properties in this group range from a gas (nitrogen) to a solid nonmetal (phosphorous) to a dense metal (bismuth) * Nitrogen from air

23 Nitrogen Family (Group 5A) * 5 valence electrons, forms -3 ions * Properties in this group range from a gas (nitrogen) to a solid nonmetal (phosphorous) to a dense metal (bismuth) * Nitrogen from air is used to produce fertilizers * Phosphorous is used in our bodies to control reactions and release energy from food; Exists in several forms with different properties: -->White = bursts into flame when in contact with oxygen -->Red = less reactive-used to make matches 23

24 Oxygen Family (Group 6A) * 6 valence electrons, form -2 ions * 3 nonmetals & 2 metalloids * Oxygen-most abundant element in earth s crust. Complex organisms need oxygen to release energy in food; ozone - another form of oxygen (O 3 ) that is beneficial in the atmosphere to block ultraviolet (UV) rays from sun; ozone is an irritant to lungs & eyes at ground level * Sulfur is combined with H 2 & O 2 to make sulfuric acid; More sulfuric acid is produced in the US than any other chemical 24

25 Halogens (Group 7A) * 7 valence electrons, form -1 ion * all elements in this group are highly reactive * Fluorine & chlorine are gases most reactive non-metal!! * Fluorine used to prevent tooth decay * chlorine used to kill bacteria in drinking water & swimming pools * bromine is a fast evaporating liquid * iodine is a solid that sublimes; Your body needs iodine to keep your thyroid gland working properly (controls the speed at which reactions occur in your body); Found in seafood and salt. 25

26 Noble Gases (Group 8A) * 8 valence electrons; tend not to form an ion * Don t bond with other elements * Colorless, odorless and unreactive * Used in neon lights 26

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28 Transition Metals (Groups 3-12, aka ß-block) * Form multiple ions * Are mildly reactive * Many are good conductors of heat & electricity Lanthanide/Actinide (Rare Earth elements) *often found in earth s crust in combination with other members of this group. 28

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AIM: SWBAT determine the location of metals, nonmetals and metalloids on the periodic table. What is another name for a column in the periodic table?

th Grade Science Metals, nonmetals and metalloids Name Date: UNIT 1 LESSON 1 Do Now AIM: SWBAT determine the location of metals, nonmetals and metalloids on the periodic table Directions: Answer the following