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PERIODIC TABLE OF THE ELEMENTS Click Below & Enjoy a Periodic Table Tune! periodic table song WRITE Founding Scientists • Mendeleev: proposed 1st periodic table where elements were arranged according to ATOMIC MASS. • Moseley: revised periodic table and arranged elements according to ATOMIC NUMBER. Elements are arranged: Vertically into Families Horizontally Into Periods Why? If you looked at one atom of every element in a group or family you would see… Each atom has the same number of electrons in it’s outermost shell, the same number of valence electrons. • An example… The group 2 atoms all have 2 electrons in their outer shells Be (Beryllium) Atom Mg (Magnesium) Atom WRITE Families • The number of outer or “valence” electrons in an atom effects the way an atom bonds. • The way an atom bonds determines many properties of the element. • This is why elements within a family usually have similar properties, both chemical and physical. If you looked at an atom from each element in a period you would see… Each atom has the same number of electron holding shells. An example… The period 4 atoms each have 4 electron containing shells 4th Shell K (Potassium) Kr (Krypton) Atom Atom Fe (Iron) Atom ACTIVITY TO GET A BETTER UNDERSTANDING AND APPRECIATION FOR THE STRUGGLES AND METHODOLOGY EARLY SCIENTISTS USED TO ARRANGE THE ELEMENTS AND FIND TRENDS IN THEIR PROPERTIES, YOU WILL NOW COMPLETE THE INDEX CARD ACTIVITY. Each FAMILY has distinct PHYSICAL AND CHEMICAL properties The periodic table is divided into several FAMILIES based on the properties of different atoms. Label your periodic table with the following families of elements, color coding them if you want: WRITE Alkali Metals Soft, silvery colored metals Very reactive!!! CLICK ON THE LINK BELOW TO VIEW A VIDEO: reactions of alkali metals Alkali Metals reacting with water: • • • • • Li (Lithium) Na (Sodium) K (Potassium) Rb (Rubidium) Cs (Cesium) What would you expect from Francium?!?! WRITE Reactivity of Metals • As observed on the video, lithium is reactive, sodium is more reactive, potassium is even more reactive! • Cesium blows out the wall of the glass container!!! • Label your periodic table with the following: • Most reactive metals are in the bottom left of the periodic table! Alkaline Earth Metals Silvery-White Metals Fairly reactive Many are found in rocks in the earth’s crust Click on the link below to view a video reactions of the alkaline earth metals WRITE Reactivity of Metals • Once again, as seen on the video, the reactivity of the alkaline earth metals increases as we go down the family! • However, these metals are not as reactive as the alkali metals in the same period! • So Mg is less reactive than Na, but more reactive than Be!!! • Location allows prediction of reactivity! Transition Metals Most are good conductors of electricity Malleable (easily bent/hammered into wires or sheets) Click on the link below to view a video: properties of transition metals How many things can you think of that have transition metals in them? Metalloids elements highlighted in pink These elements have properties of both metals and non-metals Highlight these on your periodic table What are semiconductors (metalloids) used in? Si (Silicon) and Ge (Germanium) are very important “semi-conductors” Halogens Most are Poisonous Fairly reactive Chlorine Gas was used as a chemical weapon during World War I. It was used by the Nazis in World War II. CLICK BELOW TO VIEW A VIDEO OF THE HALOGENS REACTIVITY OF THE HALOGENS Reactivity of the Nonmetals • As observed on the video, fluorine is the most reactive of all of the nonmetals! • Most reactive nonmetals are at the top right of the periodic table (excluding the noble gases of course)! • Label your periodic table accordingly!! • Most reactive nonmetal WRITE Noble Gases Unreactive Gases at room temperature Jellyfish lamps made with noble gases artist- Eric Ehlenberger Colors Noble Gases produce in lamp tubes: • Ne (Neon): orange-red • Ar (Argon): pale lavender • He (Helium): pale peach • Kr (Krypton): pale silver • Xe (Xenon): pale, deep blue Lanthanide Series Actinide Series Periodic Table & Trends repeating or cyclical patterns WRITE on the table Atomic Radius (pm) 250 200 150 100 50 0 0 5 10 Atomic Number 15 20 Periodic Law WRITE When elements are arranged in order of increasing atomic #, elements with similar properties appear at regular intervals. 250 K Atomic Radius (pm) Na 200 Li 150 100 Ar 50 Ne 0 0 5 10 Atomic Number 15 20 ATOMIC RADIUS TRENDS LARGEST ONES ARE THE ALKALI METALS IN THE ROW SMALLEST ONES ARE THE NOBLE GASES IN THE ROW WRITE Atomic Radius Increases DOWN Decreases ACROSS 1 2 3 4 5 6 7 WRITE Atomic Radius Down a Family: Atomic Radius INCREASES WHY? More energy levels with each consecutive period. Across a Period: Atomic Radius DECREASES WHY? Effective nuclear force increases because the attraction of the nucleus for the electron cloud increases. WRITE Ionization Energy the energy required to remove an electron from an atom. • Across a Period: Ionization Energy INCREASES WHY? It becomes increasingly more difficult to remove an electron from an atom. • Down a Group: Ionization Energy DECREASES WHY? It becomes increasingly less difficult to remove an electron from an atom. IONIZATION ENERGY WRITE TRENDS HIGHEST I.E. BELONG TO THE NOBLE GASES LOWEST I.E. BELONG TO THE ALKALI METALS WRITE Ionization Energy First Ionization Energy Increases to the RIGHT Decreases DOWN a family 1 2 3 4 5 6 7 WRITE Ionic Radius Cations (+) atoms lose eget smaller Anions (–) atoms gain eget larger © 2002 Prentice-Hall, Inc. WRITE Electronegativity the tendency for an atom to attract electrons to itself when it is chemically combined with another element ECl > ENa Example: NaCl Cl takes e- away from Na ELECTRONEGATIVITY WRITE TRENDS HIGHEST ELECTRONEGATIV ITY IS FLUORINE fluorine chlorine bromine LOWEST ELECTRONEGATITIES BELONG TO THE NOBLE GASES ELECTRONEGATIVITY WRITE Electronegativity Across a Period: Electronegativity INCREASES WHY? Fluorine has a very high tendency to attract electrons within a bond due to a high effective nuclear force. Down a Group: Electronegativity DECREASES WHY? Elements in a group have decreasing effective nuclear force. Atoms tend to give up electrons more easily the lower you go on the periodic table. WRITE Summary of Trends Put these directly on your periodic table as a summary of the trends Increasing Ionization Energy Increasing Electronegativity Decreasing Size Decreasing Ionization Energy Decreasing Electronegativity Increasing Size Examples • Which atom has the larger radius? Be or Ba Ba Ca or Br Ca Examples • Which atom has the higher 1st I.E.? N or Bi N Ba or Ne Ne Examples • Which particle has the larger radius? S Al or 2S 2S or 3+ Al Al COMPARISON OF METALS WRITE AND NONMETALS METALS NONMETALS • • • • Lose electrons easily Low ionization energies Low electronegativities Form positive ions that are smaller than the atoms from which they come • • • • Gain electrons easily High ionization energies High electronegativities Form negative ions that are larger than the atoms from which they come For the Test, know the following • The people and vocabulary • The families and periods • The trends in reactivity, electronegativity, ionization energy, and size (explanations) • Metal/nonmetal differences