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Name: Regents Chemistry: Mr. Palermo Notes: Unit 4: Periodic Table MIND BLOWN!!!! www.mrpalermo.com Name: Key Ideas: The placement or location of elements on the Periodic Table gives an indication of physical and chemical properties of that element. The elements on the Periodic Table are arranged in order of increasing atomic number. (3.1y) Elements can be classified by their properties and located on the Periodic Table as metals, nonmetals, metalloids (B, Si, Ge, As, Sb, Te), and noble gases. (3.1v) Elements can be differentiated by their physical properties. Physical properties of substances, such as density, conductivity, malleability, solubility, and hardness, differ among elements. (3.1w) Elements can be differentiated by chemical properties. Chemical properties describe how an element behaves during a chemical reaction. (3.1x) Some elements exist in two or more forms in the same phase. These forms differ in their molecular or crystal structure, and hence in their properties. (5.2f) For Groups 1, 2, and 13-18 on the Periodic Table, elements within the same group have the same number of valence electrons (helium is an exception) and therefore similar chemical properties. (3.1z) The succession of elements within the same group demonstrates characteristic trends: differences in atomic radius, ionic radius, electronegativity, first ionization energy, metallic/nonmetallic properties. (3.1aa) The succession of elements across the same period demonstrates characteristic trends: differences in atomic radius, ionic radius, electronegativity, first ionization energy, metallic/nonmetallic properties. (3.1bb) www.mrpalermo.com 10/31/15& UNIT 4: PERIODIC TABLE LESSON 4.1 DEVELOPMENT OF THE PERIODIC TABLE W W W. M R PA L E R M O . C O M MENDELEEV • Organized the elements based upon ATOMIC MASS PERIODIC LAW • The properties of elements are periodic functions of their atomic numbers. MOSLEY • Developed the Modern Day Table • Organized elements by # of PROTONS (Atomic Number) THE RESULT….. • Can fill in gaps to predict undiscovered elements and their properties 1& 10/31/15& HOW IS THE TABLE ORGANIZED? Period Group • PERIODS (horizontal rows) - Equal to the # of energy levels (shells) • GROUPS (vertical columns) - elements have the SAME # of VALENCE ELECTRONS resulting in similar chemical properties • # of period tells us the # of e- SHELLS (AKA principal energy level) • properties of elements change drastically ACROSS A PERIOD (metals ! metalloids/semi-metals ! nonmetals) • # of VALENCE ELECTRONS increases from left to right (1 ! 8) • Ex: K is in period 4 REACTIVITY OF ELEMENTS • Determined by # of valence electrons • All atoms (except Hydrogen) want 8 VALENCE ELECTRONS to become STABLE (full valence shell) • Called a STABLE OCTET EXAMPLE: • The closer to a stable octet the MORE REACTIVE the element is. Which element is in Group 2 and has 4 energy levels? ****Period 1 elements need 2 electrons to have a full valence shell NOT 8 2& 10/31/15& EXAMPLE: • Which two elements have similar chemical properties and why? Na, K, Li, Be • Na & K are in the same group and have the same number of valence electrons 1 METALS, NONMETALS, METALLOIDS H 3 4 5 6 7 2 Li Be B C N O F Ne 3 4 5 6 7 8 9 10 Al Si PNonmetals S Cl Ar 13 14 15 16 Na Mg 11 12 17 18 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 19 20 21 22 23 24 28 Y 39 Rb Sr 37 W W W. M R PA L E R M O . C O M He 1 2 LESSON 4.2 CATEGORIES & PROPERTIES OF ELEMENTS 38 25 31 32 Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te 40 49 50 51 27 29 30 METALS 41 42 43 Cs Ba He Ta W 55 56 72 74 Fr Ra 87 88 Ω 26 73 44 36 I Xe 53 54 Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 75 77 78 81 82 83 80 52 35 46 79 48 34 45 76 47 33 84 85 86 ELEMENT GROUPS Rf Db Sg Bh Hs Mt 104 105 106 107 108 Metalloids 109 La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 57 • • • • 58 59 60 Ac Th Pa U 89 92 90 91 61 62 63 64 65 66 Np Pu Am Cm Bk Cf 93 94 95 96 97 98 67 68 69 70 71 Es Fm Md No Lr 99 100 101 102 103 GROUP 1: ALKALINE METALS GROUP 2: ALKALINE EARTH METALS 1 valence electron Lose 1 electron to form +1 ions Extremely reactive with water Most REACTIVE metal is Fr • 2 valence electrons • Lose 2 electrons to form +2 ions • Fairly reactive in water 3& 10/31/15& GROUPS 3-12: TRANSITION METALS • Least reactive metals • Form COLORED IONS in solution GROUP 18: NOBLE GASES • Unreactive or INERT • Stable octet (8 valence electrons) - Exception is He which has 2 valence electrons - monoatomic PROPERTIES OF METALS GROUP 17: HALOGENS • 7 valence electrons • Gain 1 electron to for -1 ions • Most REACTIVE nonmetal is F HYDROGEN • Not officially part of a group • Nonmetal • Gas at STP METALS HAVE A “SEA” OF MOBILE ELECTRONS….RESULTS IN ELECTRICAL CONDUCTIVITY • Malleable (can be hammered or rolled into thin sheets) • Ductile (can be drawn into a wire) • Excellent conductors of heat and electricity • Luster (shiny) • Lose electrons to form cations • Solid @ STP (except Hg) 4& 10/31/15& WHY DO METALS HAVE LUSTER? • Metals easily absorb light energy which excites the delocalized electrons and when they fall back to lower energy levels they emit light (luster) WHY ARE ALLOYS (MIXTURES OF METALS) STRONGER THAN PURE METALS? • Alloys such as brass (a mixture of copper and zinc) are harder than the original metals because the irregularity in the structure helps to stop rows of atoms from slipping over each other WHY ARE METALS MALLEABLE AND DUCTILE? • Metals consist of layers of atoms that can slide over each other METALLIC CHARACTER • How much “like a metal” an element is • Franicium is most metallic - Closer to Fr more metallic…further from Fr least metallic PROPERTIES OF METALLOIDS • Semiconductors (Good/moderate conductor) • Luster (like metals) and Brittle (like nommetals) • Used for making computer microchips 5& 10/31/15& PROPERTIES OF NON-METALS SUMMARY OF THE CATEGORIES OF ELEMENTS • Poor conductors of heat and electricity • Brittle (shatter when struck) • Dull • Tend to gain electrons to form anions ATOMIC RADIUS • SIZE of the atom • Located on Table S LESSON 4.3 TRENDS IN ATOMIC RADIUS W W W. M R PA L E R M O . C O M ACROSS A PERIOD TREND IN ATOMIC RADIUS • Trend: DECREASES • Why? • Nuclei have greater NUCLEAR PULL (larger positive charges) which PULL electrons CLOSER Atomic radius decreases 6& 10/31/15& 13 + DOWN A GROUP Greater nuclear charge 17 + Cl Al • Trend: INCREASES • Why? • GREATER number of ENERGY SHELLS (indicated by the PERIOD #) Atomic Radius increases Less nuclear charge TO FIGURE OUT: • Pick a Period (row) or Group (column) and note the values of the elements USING TABLE “S” TO DETERMINE TRENDS IN ATOMIC RADIUS • Example: Going across a period what is the trend in atomic radius? 7& 10/31/15& • Pick an element on the left side of the periodic table and pick another element on the right side of the same period. 130 pm " 60 pm Trend is decreasing ION SIZE- METALS Ion radius SMALLER than atomic radius Why? • Metal ions LOSE electrons to form Cations • RECALL….. ION SIZE- NONMETALS Ion radius LARGER than atomic radius • Why? • Nonmetal ions GAIN electrons to for anions. • © 2002 Prentice-Hall, Inc. 8& 10/31/15& RECALL……REACTIVITY Metals • LESSON 4.4 TRENDS IN IONIZATION ENERGY & ELECTRONEGATIVITY • • Non Metals Decreases across period Increases down group • Reason: The larger the atom the weaker the nuclear pull and the more easily you lose electrons and become stable • • Increases across period Decreases down group Reason: The smaller the atom the greater the nuclear pull (+) and the more easily it attracts electrons (-) IONIZATION ENERGY e - + e - + Smaller atom • Energy required to REMOVE the most loosely bound ELECTRON in the valence shell • Located on Table S Larger atom TREND IN IONIZATION ENERGY • INCREASES across a PERIOD • Why? • Stronger NUCLEAR PULL makes it more difficult to remove electrons Less nuclear charge e - Greater nuclear charge e - 13 + 17 + Cl Al 9& 10/31/15& TREND IN IONIZATION ENERGY e - • DECREASES down a GROUP • Why? • Larger atomic radius means LESS NUCLEAR PULL on outer electrons e - + + EXAMPLE • What is trend in atomic radius going down a group? • Why does this trend occur? • 496 • 419 • 403 Trend is decreasing larger atomic radius equals less nuclear pull on valence e- ELECTRONEGATIVITY • Measure of the ATTRACTION for electrons • Located on Table S • FLUORINE most electronegative (4.0) • The closer an atom is to Fluorine the HIGHER the electronegativity • Scale of 0 - 4 10& 10/31/15& TREND IN ELECTRONEGATIVITY • INCREASES across period • Why? Less nuclear charge e - Greater nuclear charge e - - Greater NUCLEAR PULL(charge) to attract electrons 17 + 13 + Cl Al TREND IN ELECTRONEGATIVITY • DECREASES down group • Why? - Larger atomic radius means LESS NUCLEAR PULL to attract electrons to the valence shell e e - + + The Trend is INCREASING EXAMPLE a. What is the trend in electronegativity across a period? b. Why does this trend occur? 11& 10/31/15& Summary Periodic Property Variation across a Period Variation down a Group Metallic Character Decreases Increases Atomic Radius Decreases Increases Ionization Energy Increases Decreases Electronegativity Increases Decreases 12&