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1 Anything in black letters = write it in your notes (‘knowts’) Lesson 6The Periodic TableAnything in black letters = write it in your notes (‘knowts’)
2 Objectives for Lesson 6 Section 1 – Organizing the Elements Section 2 – Periodic TrendsDescribe ways in which the modern periodic table is organizedUnderstand electron configuration patterns in the periodic tableDescribe and explain trends in the periodic table
3 Section 1 – Organizing the Elements Dmitri Mendeleev (1869) – created 1st modern periodic table.
4 Mendeleev arranged elements with similar properties. He also left gaps where proposed elements should be.These gaps were later filled in as more elements were discovered.Ga & Ge Discovered laterSimilar properties
5 Mendeleev’s table was an accepted success because it predicted the properties of elements that had not yet been discovered.Woo Hoo!
6 Today’s periodic table is arranged in order of increasing atomic number (not mass). Also, elements with similar chemical properties are placed in the same vertical column.
7 Columns are called groups or families. Horizontal rows are called periods.
8 Valence Electrons – Electrons in the highest occupied energy level; maximum of 8. Elements in the same column have similar properties because they have the same number of valence electrons.
9 8 is the maximum number of valence electrons Electrons in the s and p orbitals of the outer shell are the valence electrons.8 is the maximum number of valence electrons
10 Sodium: 1s22s22p63s1 Magnesium: 1s22s22p63s2 Fluorine: 1s22s22p5 The Octet Rule –Atoms tend to gain or lose electrons to have 8 e-Sodium: 1s22s22p63s1Magnesium: 1s22s22p63s2Fluorine: 1s22s22p5Nitrogen: 1s22s22p3
11 Sodium: 1s22s22p63s1 Magnesium: 1s22s22p63s2 Fluorine: 1s22s22p5 The noble gases are chemically stable because they have a full outer energy level (valence).Atoms tend to gain or lose electrons to have 8 e-Sodium: 1s22s22p63s1Magnesium: 1s22s22p63s2Fluorine: 1s22s22p5Nitrogen: 1s22s22p3
12 Electron configurations for Group 1 (valence e- underlined)1s11s22s11s22s22p63s11s22s22p63s23p64s11s22s22p63s23p64s23d104p65s1[Xe]6s1[Rn]7s1
13 1s22s22p51s22s22p63s23p5Get the idea?...Why is it called the Periodic Table of the Elements?The properties of the elements repeat going across each row.
14 Three broad classes of elements; metals, metalloids, nonmetals
15 Metals – good conductors of heat and electricity, shiny, most are solid at room temp (except Hg), malleable, ductileNonmetals – not metals!, most are gases at room tempMetalloids – can show properties of both metals and nonmetals
18 Practice Explain why Mendeleev’s table was an accepted success. Why is the table of elements called the “periodic” table of elements?State 4 properties of metals.Explain the reason that elements in the same column have similar chemical properties?How can you tell if an elements is a metal, nonmetal or metalloid from the periodic table?
19 6. Name an element that is part of the Halogen familyAlkali metal familyAlkaline earth metal familyTransition metalsInner transition metalsNoble gas family7. A horizontal row in the periodic table is called a _____.
20 8. Write the electron configuration for NitrogenChlorineRubidium9. How many valence electrons are in each element from question 8?
23 Atomic size generally decreases from left to right across a period. As Z increases across a row, the +/- electrical attraction increases, making the atom smaller.As Z increases down a group, another energy level is added to the atom which ‘shield’ the outer electrons from this nuclear attraction.
24 Ion – atom or group of atoms that has a positive or negative charge. Ions are formed when electrons are transferred between atoms.
25 Cation – ion with a positive charge. Anion – ion with a negative charge.
26 Metals tend to form cations Nonmetals tend to form anions
27 1st ionization energy = 520 kJ/mol 2nd ionization energy = 7297 kJ/mol Ionization Energy – energy required to remove an electron from an atom.lithium +1 ionlithium atom1st ionization energy = 520 kJ/mollithium ionLithium +2 ion2nd ionization energy = 7297 kJ/mol
28 1st ionization energy = 520 kJ/mol 2nd ionization energy = 7297 kJ/mol Ionization Energy – energy required to remove an electron from an atom.lithium +1 ionlithium atom1st ionization energy = 520 kJ/mollithium ionLithium +2 ion2nd ionization energy = 7297 kJ/mol
29 Ionization Energies of Some Common Elements SymbolFirstSecondThirdH1312He (noble gas)23725247Li520729711,810Be899175714,840C108623524619O131433915301F168133756045Ne (noble gas)208039636276Na49645656912Mg73814507732S99922603380Ar (noble gas152026653947K41930964600Ca59011464941
32 What does 1st ionization energy mean? Explain why the 2nd ionization energy of Li and Na is so much higher than the 1st ionization energy.Explain why the 1st ionization energy of Na is smaller than Li.Why are the ionization energies of the noble gases so large?
33 Electronegativity – tendency of an atom to attract electrons of another atom. Metals have low e-neg values,Nonmetals have high e-neg values
35 Electronegativity Values for Selected Elements H2.1Li1.0Be1.5B2.0C2.5N3.0O3.5F4.0Na0.9Mg1.2AlSi1.8PSClK0.8CaGa1.6GeAsSe2.4Br2.8RbSrIn1.7SnSb1.9TeICs0.7BaTlPbBi
36 Lesson 6 PracticeHow does the size of an atom change from left to right a) across a period? b) down a column?Give the explanation for question 1.What is an ion and how are they formed?Metals tend to form _____ ions and nonmetals tend to form _____ ions.Define Ionization Energy.Describe the trend in ionization energy in the periodic table.
37 Define electronegativity. Which atom is the a) most electronegative, b) least electronegative?Which atom has the highest ionization energy?How do electronegativity values differ between metals and nonmetals?
39 Lesson 6 Quiz Review Terms to know: valence electron, cation, anion, electronegativity,ionization energy (1st & 2nd)
40 Things to know:Metal, nonmetals, metalloids locations4 properties of metalsmetals form cations, nonmetals form anionsfamily names (alkali, alkaline earth, noble, halogens, transition and inner transition)electronegativity and ionization energy trendselectron configurations (w/out aufbau diagram)
41 Possible Short Answer Questions: 1. Why was Mendeleev’s table an accepted success?2. Why is the periodic table called the “periodic” table?3. What causes elements in the same column to have similar chemical properties?4. What is an ion and how are ions formed?5. Why is the 2nd ionization energy of Na so much larger than the 1st ionization energy?
42 Energy levels can also be called electron shells