CH 101 1st Edition Lecture 7 Outline of Last Lecture I The Schrodinger Model of the Atom A Nodes II Introduction to Quantum Numbers III The Pattern Within Energy Levels IV What Orbitals Look Like A Electron Configuration V Quantum Numbers on the Periodic Table Outline of Current Lecture I Reviewing Quantum Numbers II Atomic Structure and Properties A Core Electrons B Valence Electrons III Effective Nuclear Charge IV Trends on the Periodic Table Current Lecture V Reviewing Quantum Numbers Quantum Number Define Limits n Represents the 1 2 3 4 5 etc energy level An integer greater than or equal to one Orientation 0 1 2 3 etc l An integer less than the value of n ml Orbital lto lif l 1 ml 1 0 1 3 orbitals These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute ms Spin Ex If n 4 then what are the possible values for l ml and ms l Is any integer less than n therefore l could equal 3 2 1 or 0 ml Is l to l thereforeml could equal 3 2 1 0 1 2 3 7 2 1 0 1 2 5 1 0 1 3 0 1 And ms can only equal VI Atomic Structure and Properties C Core Electrons The tightly bounded electrons of filled energy levels in an atom Core electrons are unaffected by chemical reactions because they don t want to give or take electrons D Valence Electrons The loosely bounded electrons that are on the outermost shell of an atom that are involved in chemical bonding The valence electrons are shown as the highest energy level in the s block and the partially filled levels in whatever block it s in Ex What is the valence electron configuration of Sn Determine the electron configuration of Sn using Lecture 6 notes 5s2 5p2 3d10 Electron configuration of Sn Remember that the Valence electron configuration only has the s block and the valence electrons 5s2 5p2 The valence electron configuration incudes s block electrons and the unfilled electrons in the p block VII Effective Nuclear Charge The effective nuclear charge is the level of attraction an electron feels toward the nucleus The effective nuclear charge can be found using this equation Zeffective Z Z atomic mass shielding constant This equation tells you that as the atomic number goes up the effective nuclear charge goes up Ex Which atom has the lowest Zeff Pb Ar or S Look at the atomic numbers of these elements Pb 82 Ar 18 S 16 S has the lowest Zeff Review the trend of effective nuclear charge and see that the lower the atomic number the lower the effective charge VIII Trends on the Periodic Table On the Periodic Table there are different trends for size electronegativity effective charge and ionization energy Trend for Size of the Atom The largest atoms are in the bottom left corner and the smaller atoms are in the top right corner Trend for the Electronegativity of an Atom The smaller an atom is the more electronegative it is This is because the smaller atoms have a stronger pull on their electron cloud and when bonded with another atom it will take some of its electrons and pull the electron cloud more toward its self Most electronegative Least electronegative Trend for the Effective Charge of an atom The effective charge increases as you move right and as you move down it increases with atomic number However the effective charge tends to drop between rows so just remember that it increases as you go right and that the upper right hand side has the Trend for the Ionization Energy of an atom The ionization energy increases as you move up and to the right of the periodic table The ionization trend inversely correlates to the trend of the size of the atom The larger the atom the weaker the ionization energy This relationship occurs because the larger the atom is the farther away the outer shell of electrons is from the nucleus which make is easier for that atom to lose its outer electrons giving it a low ionization energy High ionization energy Low ionization energy