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Electron Configuration and the Periodic Table We’ve compared Bohr’s model and the Quantum Mechanical model... Bohr’s Model. QM Model No Sub-levels Has Sub-levels 3 2 1 34 2 1 3d __ __ __ __ __ 4s __ 3p __ __ __ 3s __ 2p __ __ __ 2s __ 1s __ Orbital Diagram for Nitrogen (7e-) We’ve learned how to draw orbital diagrams mmm 5p __ 4d __ 5s __ 4p __ 3d __ 4s __ 3p __ 3s __ 2p __ 2s __ 1s __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ Orbital Diagram for Chlorine (17 e-) Here’s the first 13 electrons. Where does the next electron go? 5p __ 4d __ 5s __ 4p __ 3d __ 4s __ 3p __ 3s __ 2p __ 2s __ 1s __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ Orbital Diagram for Chlorine (17 e-) Now, let’s do the electron configuration. 1s2 2s2 2p6 3s2 3p5 5p __ 4d __ 5s __ 4p __ 3d __ 4s __ 3p __ 3s __ 2p __ 2s __ 1s __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ Orbital Diagram for Tellurium (52 e-) When we have large atoms, the electron configuration gets very long! 5p __ 4d __ 5s __ 4p __ 3d __ 4s __ 3p __ 3s __ 2p __ 2s __ 1s __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p4 But, there’s an easier way.... Hydrogen has one electron.The electron configuration is 1 1 1s 2p __ __ __ 1 H orbital 2s __ 2 diagram: 1s __ 3 4 5 6 7 Beryllium has 4 electrons. The electron configuration is 22s2 1s 1 2p __ __ __ 1 1s orbital 4 2s __ 2 2 diagram: 2s Be 1s __ 3 4 5 6 7 Nitrogen has 7 electrons. The electron configuration is 22s22p3 1 1s 1s 2p __ __ __ 1 orbital 7 3 2s __ 2 2 2p diagram: 2s N 1s __ 3 4 5 6 7 s1 s2 The representative elements (s and p filling) 1 1s1 1s2 p5 p6 2 2s1 2s2 p1 p2 p3 p4 2p1 2p2 2p3 2p4 2p5 2p6 3 3s1 3s2 3p1 3p2 3p3 3p4 3p5 3p6 4 4s1 4s2 4p1 4p2 4p3 4p4 4p5 4p6 5 5s1 5s2 5p1 5p2 5p3 5p4 5p5 5p6 6 6s1 6s2 6p1 6p2 6p3 6p4 6p5 6p6 7 7s1 7s2 7p1 7p2 7p3 7p4 7p5 7p6 s1 s 2 1 1s1 The electron config. for Nitrogen is 1s22s22p3 1s2 p5 p6 2 2s1 2s2 p1 p2 p3 p4 2p1 2p22p3 2p4 2p5 2p6 3 3s1 3s2 3p1 3p2 3p3 3p4 3p5 3p6 4 4s1 4s2 4p1 4p2 4p3 4p4 4p5 4p6 5 5s1 5s2 5p1 5p2 5p3 5p4 5p5 5p6 6 6s1 6s2 6p1 6p2 6p3 6p4 6p5 6p6 7 7s1 7s2 7p1 7p2 7p3 7p4 7p5 7p6 s1 s 2 2 2s1 2s2 The electron config. for Potassium (K) is 2 1s 2 2 6 2 6 1 1s 2s 2p 3s 3p 4s p1 p2 p3 p4 p5 p6 2p1 2p22p3 2p4 2p5 2p6 3 3s1 3s2 3p1 3p2 3p3 3p4 3p5 3p6 4 4s1 4s2 4p1 4p2 4p3 4p4 4p5 4p6 5 5s1 5s2 5p1 5p2 5p3 5p4 5p5 5p6 6 6s1 6s2 6p1 6p2 6p3 6p4 6p5 6p6 7 7s1 7s2 7p1 7p2 7p3 7p4 7p5 7p6 1 1s1 The transition elements (d and f filling) 1s2 1s1 2s1 2s2 The d block is 1 energy level lower that its s & p neighbors 2p1 2p2 2p3 2p4 2p5 2p6 3p1 3p2 3p3 3p4 3p5 3p6 3s1 3s2 4s1 4s2 3d1 3d2 3d3 3d4 3d5 3d6 3d7 3d8 3d9 3d104p1 4p2 4p3 4p4 4p5 4p6 5s1 5s2 4d1 4d2 4d3 4d4 4d5 4d6 4d7 4d8 4d9 4d105p1 5p2 5p3 5p4 5p5 5p6 6s1 6s2 5d1 5d2 5d3 5d4 5d5 5d6 5d7 5d8 5d9 5d106p1 6p2 6p3 6p4 6p5 6p6 1 3 4 7s1 7s2 6d1 6d2 6d3 6d4 6d5 6d6 6d7 6d8 6d9 6d107p 7p2 7p 7p 7p5 7p6 4f1 4f2 4f3 4f4 4f5 4f6 4f7 4f8 4f9 4f10 4f11 4f12 4f134f14 5f1 5f2 5f3 5f4 5f5 5f6 5f7 5f8 5f9 5f10 5f11 5f12 5f135f14 The f block is 2 energy levels lower that its s & p neighbors QM Model Sub-levels overlap See how 4s is lower energy than 3d 4 3 2 1 4d __ 5s __ 4p __ 3d __ 4s __ 3p __ 3s __ 2p __ 2s __ 1s __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ The transition elements (d and f filling) 1s2 1s1 2s1 2s2 The d block is 1 energy level lower that its s & p neighbors 2p1 2p2 2p3 2p4 2p5 2p6 3p1 3p2 3p3 3p4 3p5 3p6 3s1 3s2 4s1 4s2 3d1 3d2 3d3 3d4 3d5 3d6 3d7 3d8 3d9 3d104p1 4p2 4p3 4p4 4p5 4p6 5s1 5s2 4d1 4d2 4d3 4d4 4d5 4d6 4d7 4d8 4d9 4d105p1 5p2 5p3 5p4 5p5 5p6 6s1 6s2 5d1 5d2 5d3 5d4 5d5 5d6 5d7 5d8 5d9 5d106p1 6p2 6p3 6p4 6p5 6p6 1 3 4 7s1 7s2 6d1 6d2 6d3 6d4 6d5 6d6 6d7 6d8 6d9 6d107p 7p2 7p 7p 7p5 7p6 4f1 4f2 4f3 4f4 4f5 4f6 4f7 4f8 4f9 4f10 4f11 4f12 4f134f14 5f1 5f2 5f3 5f4 5f5 5f6 5f7 5f8 5f9 5f10 5f11 5f12 5f135f14 The f block is 2 energy levels lower that its s & p neighbors The electron config. for Europium (Eu) is 1s1 2s1 2s2 1s2 5s2 2s2 2p6 3s2 3p6 4s2 4d10 5p6 6s2 4f7 3d10 4p6 1s2 2p1 2p2 2p3 2p4 2p5 2p6 3p1 3p2 3p3 3p4 3p5 3p6 3s1 3s2 4s1 4s2 3d1 3d2 3d3 3d4 3d5 3d6 3d7 3d8 3d9 3d104p1 4p2 4p3 4p4 4p5 4p6 5s1 5s2 4d1 4d2 4d3 4d4 4d5 4d6 4d7 4d8 4d9 4d105p1 5p2 5p3 5p4 5p5 5p6 6s1 6s2 5d1 5d2 5d3 5d4 5d5 5d6 5d7 5d8 5d9 5d106p1 6p2 6p3 6p4 6p5 6p6 1 3 4 7s1 7s2 6d1 6d2 6d3 6d4 6d5 6d6 6d7 6d8 6d9 6d107p 7p2 7p 7p 7p5 7p6 4f1 4f2 4f3 4f4 4f5 4f6 4f7 4f8 4f9 4f10 4f11 4f12 4f134f14 5f1 5f2 5f3 5f4 5f5 5f6 5f7 5f8 5f9 5f10 5f11 5f12 5f135f14 The f block is 2 energy levels lower that its s & p neighbors • So, we don’t have to draw orbital diagrams to get the electron configurations. We can just look at the periodic table. ....That makes it easier. • Now, we’re going to learn a short-cut way to write electron configurations . ....That’ll make it even easier. The Shortcut electron configurations made EZ The Shorthand • Write symbol of the noble gas before the element, in [ ]. • Then, the rest of the electrons. • Aluminum’s full configuration: 1s22s22p63s23p1 • previous noble gas Ne is: 1s22s22p6 • so, Al is: [Ne] 3s23p1 The Shorthand Again Sn- 50 electrons The noble gas before it is Kr Takes care of 36 Next 5s2 Then 4d10 Finally 5p2 [ Kr ] 5s2 4d10 5p2 Find “the element” on the PT Go back in atomic numbers until you hit a Noble Gas Write the symbol for the noble gas in brackets Then write the electrons on the line for “the element” Looks hard, is EZ Write a shortcut electron configuration for Mg [Ne] 3s2 Cl [Ne] 3s2 3p5 V [Ar] 4s2 3d3 Bi [Xe] 6s2 4f14 5d10 6p3 Assignment 1.) Do shortcut electron configurations for: C (carbon) Sr (strontium) Se (selenium) U (uranium) Xe (xenon) 2.) Do long electron configurations just using the periodic table (not using orbital diagrams) for: S (sulfur) Cr (chromium) When two atoms come together to bond, which electrons do you think will be involved in bonding, the inner electrons or the outer electrons? The outer electrons! Valence electrons The electrons in the highest main energy level are called valence electrons. Valence electrons Inner electrons The periodic table was made this way before the electron configurations were known. It was based on putting similar elements in vertical columns. How do these fit together? 1s2 1s1 2s1 2s2 2p1 2p2 2p3 2p4 2p5 2p6 3s1 3s2 3p1 3p2 3p3 3p4 3p5 3p6 4s1 4s2 3d1 3d2 3d3 3d4 3d5 3d6 3d7 3d8 3d9 3d104p1 4p2 4p3 4p4 4p5 4p6 5s1 5s2 4d1 4d2 4d3 4d4 4d5 4d6 4d7 4d8 4d9 4d105p1 5p2 5p3 5p4 5p5 5p6 6s1 6s2 5d1 5d2 5d3 5d4 5d5 5d6 5d7 5d8 5d9 5d106p1 6p2 6p3 6p4 6p5 6p6 1 3 4 7s1 7s2 6d1 6d2 6d3 6d4 6d5 6d6 6d7 6d8 6d9 6d107p 7p2 7p 7p 7p5 7p6 4f1 4f2 4f3 4f4 4f5 4f6 4f7 4f8 4f9 4f10 4f11 4f12 4f134f14 5f1 5f2 5f3 5f4 5f5 5f6 5f7 5f8 5f9 5f10 5f11 5f12 5f135f14 Going across a period, what happens to the number of valence electrons? Na 1s2 2s2 2p6 3s1 Mg 1s2 2s2 2p6 3s2 Al 1s2 2s2 2p6 3s2 3p1 Si 1s2 2s2 2p6 3s2 3p2 P 1s2 2s2 2p6 3s2 3p3 S 1s2 2s2 2p6 3s2 3p4 Cl 1s2 2s2 2p6 3s2 3p5 Ar 1s2 2s2 2p6 3s2 3p6 The electrons are being added to the same principal energy level Valence electrons are the electrons that are involved in bonding. Are those outer valence electrons in low or high energy levels? Valence electrons are the electrons in the highest principal energy level (the number at the beginning of the sublevel 1s or 2p or 3d etc…) It ends up that these are the s and p electrons. How many valence electrons (VE) in the following? 1s2 2s2 2p5 or [He] 2s2 2p5 1s2 2s2 2p6 or [He] 2s2 2p6 1s2 2s2 2p6 3s2 or [Ne] 3s2 1s2 2s2 2p6 3s23p64s23d104p3 or [Ar] 4s23d104p3 1 The number of valence electrons for an element 1s2 can easily be taken from its location on the periodic table 1s1 2 2s1 2s2 3 4 5 6 7 8 2p1 2p2 2p3 2p4 2p5 2p6 3s1 3s2 3p1 3p2 3p3 3p4 3p5 3p6 4s1 4s2 3d1 3d2 3d3 3d4 3d5 3d6 3d7 3d8 3d9 3d104p1 4p2 4p3 4p4 4p5 4p6 5s1 5s2 4d1 4d2 4d3 4d4 4d5 4d6 4d7 4d8 4d9 4d105p1 5p2 5p3 5p4 5p5 5p6 6s1 6s2 5d1 5d2 5d3 5d4 5d5 5d6 5d7 5d8 5d9 5d106p1 6p2 6p3 6p4 6p5 6p6 1 3 4 7s1 7s2 6d1 6d2 6d3 6d4 6d5 6d6 6d7 6d8 6d9 6d107p 7p2 7p 7p 7p5 7p6 4f1 4f2 4f3 4f4 4f5 4f6 4f7 4f8 4f9 4f10 4f11 4f12 4f134f14 5f1 5f2 5f3 5f4 5f5 5f6 5f7 5f8 5f9 5f10 5f11 5f12 5f135f14 Why do elements in the same group have similar properties??? 2 1s 1 1s1 2 2s1 2s2 2p1 2p2 2p3 2p4 2p5 2p6 3s1 3s2 3p1 3p2 3p3 3p4 3p5 3p6 3 4 5 6 7 8 4s1 4s2 3d1 3d2 3d3 3d4 3d5 3d6 3d7 3d8 3d9 3d104p1 4p2 4p3 4p4 4p5 4p6 5s1 5s2 4d1 4d2 4d3 4d4 4d5 4d6 4d7 4d8 4d9 4d105p1 5p2 5p3 5p4 5p5 5p6 6s1 6s2 5d1 5d2 5d3 5d4 5d5 5d6 5d7 5d8 5d9 5d106p1 6p2 6p3 6p4 6p5 6p6 1 3 4 7s1 7s2 6d1 6d2 6d3 6d4 6d5 6d6 6d7 6d8 6d9 6d107p 7p2 7p 7p 7p5 7p6 4f1 4f2 4f3 4f4 4f5 4f6 4f7 4f8 4f9 4f10 4f11 4f12 4f134f14 5f1 5f2 5f3 5f4 5f5 5f6 5f7 5f8 5f9 5f10 5f11 5f12 5f135f14 Trends in the Periodic Table Periodic Law The ________________ Law states: When the elements are placed in order of increasing atomic number, there is a repeating pattern seen of similar properties. Many properties of the elements change in a regular way across the periodic table. (They exhibit a trend) This is very useful because by learning just a few things, you know a lot about the elements! Atomic Radius This is basically the size of the atom (This is not the definition!!) How to find the size of an atom? Why might this be hard? How it is done x-ray crystallography This relies on the fact that when a substance crystallizes it atoms tend to form very regular patterns. X-rays bounce off the nuclei and form interference patterns that tell us the distance between the nuclei Distance between the nuclei is 64 pm What is the radius of one of the atoms? Atomic radius definition: half the distance between the nuclei of two atoms. Units are pm or 10-12 meters. 64 pm 32 pm Atomic radius Essentially how big an atom is, but is defined as half the distance between two nuclei. Remember, the nucleus is very, very tiny, so most of the volume of the atom is taken up by the ________ So let’s see what happens to the size of an atom as we go across a period… A period is a horizontal row of elements 1 2 3 4 5 6 7 Going across a period, what happens to the number of electrons? You might be inclined to think the radius should get bigger, BUT... Na 1s2 2s2 2p6 3s1 Mg 1s2 2s2 2p6 3s2 Al 1s2 2s2 2p6 3s2 3p1 Si 1s2 2s2 2p6 3s2 3p2 P 1s2 2s2 2p6 3s2 3p3 S 1s2 2s2 2p6 3s2 3p4 Cl 1s2 2s2 2p6 3s2 3p5 Ar 1s2 2s2 2p6 3s2 3p6 The electrons are being added to the same principal energy level Well, then you might next be inclined to think that the atomic radius should stay the same, BUT….. Na Mg Al Si P S Cl Ar The radius actually decreases in a period as atomic number (and electrons) increases. Why???? Na Mg Al +11 +12 +13 Na has 11 protons in the nucleus, and one electron in the 3rd energy level. Si P S Cl Ar +14 +15 +16 +17 +18 Mg has 12 protons in the nucleus, and two electrons in the 3rd energy level. While moving left to right in a period: -electrons are being added to the same shell (energy level) -the charge on the nucleus increases (more protons). This stronger pull brings the electrons in closer. Group trends • As we go down a group... • each atom has another energy level, • so the atoms get bigger. H Li 1s1 1s2 2s1 Na 1s2 2s2 2p6 3s1 K 1s2 2s2 2p6 3s2 3p6 4s1 Rb 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 Atomic Radius Increases (Same energy level electrons Lower nuclear charge) Smaller Atoms Larger Atoms Atomic Radius Increases (new electron energy levels) Shielding Effect The electrons between the nucleus and the valence electrons shield (screen) some of the attraction Valence electrons Shielding electrons Valence electron (outer) Shielding electron (inner) - I’m just not as attracted to you, nucleus. It’s not you, it’s me - + Nucleus As we go down a group what happens to the # of shielding electrons ? Shielding Electrons (2) Ne 1s2 2s2 2p6 Valence Electrons (8) Shielding Electrons(10) Ar 1s2 2s2 2p6 3s2 3p6 Valence Electrons (8) As we go down a group the number of shielding electrons increases. So shielding effect increases. As we go left to right on the periodic table what happens to the number of shielding electrons? Valence Electrons Na 1s2 2s2 2p6 3s1 Mg 1s2 2s2 2p6 3s2 Al 1s2 2s2 2p6 3s2 3p1 Si 1s2 2s2 2p6 3s2 3p2 P 1s2 2s2 2p6 3s2 3p3 S 1s2 2s2 2p6 3s2 3p4 Cl 1s2 2s2 2p6 3s2 3p5 Ar 1s2 2s2 2p6 3s2 3p6 The number of shielding electrons is constant Shielding Effect constant Shielding Effect Increases Ionization Energy • The amount of energy required to remove an electron from a neutral atom. (kJ / mol) • Removing one electron makes a 1+ ion. Metals tend to lose electrons. Any positive ion is called a cation e- Na Na+ A positive sodium ion or sodium cation. Non-Metals tend to gain electrons. Any negative ion is called a anion Cl- Cl e- A negative chlorine ion or chlorine anion (technically chloride anion) To remember + + Anions are negative Plussy the cat-ion What determines IE • nuclear charge , IE . • distance from nucleus • Shielding effect , IE , IE Does ionization energy get larger or smaller as you go across a period? (Does it get easier or harder to remove an electron as you go across a period?) Going across a period: larger. Nuclear Charge (number of protons) gets ___________ +11 +12 Size of atoms smaller. gets_________ +13 +14 +15 +16 +17 +18 Shielding stays the same. ________________ Nuclear Charge Increases, Shielding Effect Constant Size of Atoms Decreases Ionization Energy Increases Going down a column: Size of atom gets bigger. Although nuclear charge gets bigger, Shielding gets larger. Ionization Energy Decreases going down a column. Ionization Energy Increases Increases When metals react they tend to lose electrons forming cations. The lower the ionization energy for a metal, the more reactive it is IE Increases Increases When metals react they tend to lose electrons forming cations. The lower the ionization energy for a metal, the more reactive it is IE Increases Increases IE Decreases Metals are more reactive When Non-metals react they tend to GAIN electrons forming anions. The more electronegative a Non-metal is the more able it is to gain electrons and the more reactive it is. Electronegativity Increases Electronegativity Increases Elements become more Non-metallic More reactive Non-metals Elements become more metallic More reactive metals Metals are losers! (form positive ions) +1 +2 Charge varies +3 Non-metals want to gain electrons. (form negative ions) +1 0 -3 -2 -1 +2 Charge varies +3 Noble gases don’t form ions +1 0 -3 -2 -1 +2 Charge varies +3 Ionization energy INCREASE Atomic radius Increases Which has more shielding electrons? Which has more shielding electrons? The same! Which has more shielding electrons? Which has more shielding electrons? Which has more shielding electrons? Which has more shielding electrons? They have the same number! Which has more shielding electrons? Which has more shielding electrons? Which has the larger atomic radius? Which has the larger atomic radius? Which has the larger atomic radius? Which has the larger atomic radius? Which has the larger atomic radius? Which has the larger atomic radius? Which has the larger atomic radius? Which has the larger atomic radius? Which has the larger atomic radius? Which has the larger atomic radius? Which has a higher ionization energy? Which has a higher ionization energy? Which has a higher ionization energy? Which has a higher ionization energy? Which has a higher ionization energy? Which has a higher ionization energy? Which has a higher ionization energy? Which has a higher ionization energy? 1s2 1s1 2s1 2s2 2p1 2p2 2p3 2p4 2p5 2p6 3s1 3s2 3p1 3p2 3p3 3p4 3p5 3p6 4s1 4s2 3d1 3d2 3d3 3d4 3d5 3d6 3d7 3d8 3d9 3d104p1 4p2 4p3 4p4 4p5 4p6 5s1 5s2 4d1 4d2 4d3 4d4 4d5 4d6 4d7 4d8 4d9 4d105p1 5p2 5p3 5p4 5p5 5p6 6s1 6s2 5d1 5d2 5d3 5d4 5d5 5d6 5d7 5d8 5d9 5d106p1 6p2 6p3 6p4 6p5 6p6 1 3 4 7s1 7s2 6d1 6d2 6d3 6d4 6d5 6d6 6d7 6d8 6d9 6d107p 7p2 7p 7p 7p5 7p6 4f1 4f2 4f3 4f4 4f5 4f6 4f7 4f8 4f9 4f10 4f11 4f12 4f134f14 5f1 5f2 5f3 5f4 5f5 5f6 5f7 5f8 5f9 5f10 5f11 5f12 5f135f14 Light behave as waves and waves can cancel each other or add to each other + + Constructive Interference Bright light Destructive Interference Dim or no light X-ray diffraction image, the distance of nuclei can be interpreted from this image from the constructive and destructive interference of X-ray “light” Ionic Radius Definition- radius of an ion. Units-- pm (10-12 m) or A (10-10 m) How does a neutral atom become an ion? What type of ions do metals form? What type of ions do non-metals form? The Periodic Trends Explained Second Ionization Energy • the energy required to remove the second electron from an atom (kJ / mol) • Always greater than first IE, because it requires removing an e- from an atom with a 1+ charge (harder) Why is the 2nd ionization energy so high for the alkali metals? All alkali metals have 1 valence electron ( s1 ) Example Sodium: Na 1s2 2s2 2p6 3s1 Na+ 1s2 2s2 2p6 1 e- (Not too hard, low ENC) Noble Gas Configuration (full outer shell) Na2+ 1s 2 1 more e- (Difficult) 2s2 2p5 Noble Gas Configuration LOST What atom has this electron configuration? Table 14.1, p. 402 Symbol First H He Li Be B C N O F Ne 1312 2731 520 900 800 1086 1402 1314 1681 2080 Second Third 5247 7297 1757 2430 2352 2857 3391 3375 3963 11810 14840 3569 4619 4577 5301 6045 6276 Symbol First H He Li Be B C N O F Ne 1312 2731 520 900 800 1086 1402 1314 1681 2080 Second Third 5247 7297 1757 2430 2352 2857 3391 3375 3963 11810 14840 3569 4619 4577 5301 6045 6276 Ionic radius The size or radius of an ion Ionic radius follows the same trend as atomic radius (neutral atoms) for the same reasons (BUT there is a difference) Group trends • Adding energy level • Ions get bigger as you go down. Li1+ Na1+ K1+ Rb1+ Cs1+ Metals tend to lose electrons when they form ions and get smaller e- Na Na+ While Non-metals gain electrons when they form ions and get bigger Cl Cle- Otherwise the expected trend holds Periodic Trends • Across the period ions tend to get smaller because of increasing nuclear charge • Metals lose e-, but Non-metals gain eso there is a break between the two Li1+ B3+ Be2+ C4+ N3- O2- F1- Metal ions Increase in size All ions increase in size Non-metal ions Increase in size picture The transition elements (d and f filling) 1s2 1s1 2s1 2s2 The d block is 1 energy level lower that its s & p neighbors 2p1 2p2 2p3 2p4 2p5 2p6 3p1 3p2 3p3 3p4 3p5 3p6 3s1 3s2 4s1 4s2 3d1 3d2 3d3 3d4 3d5 3d6 3d7 3d8 3d9 3d104p1 4p2 4p3 4p4 4p5 4p6 5s1 5s2 4d1 4d2 4d3 4d4 4d5 4d6 4d7 4d8 4d9 4d105p1 5p2 5p3 5p4 5p5 5p6 6s1 6s2 5d1 5d2 5d3 5d4 5d5 5d6 5d7 5d8 5d9 5d106p1 6p2 6p3 6p4 6p5 6p6 1 3 4 7s1 7s2 6d1 6d2 6d3 6d4 6d5 6d6 6d7 6d8 6d9 6d107p 7p2 7p 7p 7p5 7p6 4f1 4f2 4f3 4f4 4f5 4f6 4f7 4f8 4f9 4f10 4f11 4f12 4f134f14 5f1 5f2 5f3 5f4 5f5 5f6 5f7 5f8 5f9 5f10 5f11 5f12 5f135f14 The f block is 2 energy levels lower that its s & p neighbors Which is a periodic function? 1 period Mendeleev organized his table based on repeating patterns A Periodic Function show a repeating pattern An example of a periodic function of the elements 3 2.5 2 1.5 1 0.5 0 0 10 20 30 40 50 Each bracket is a period and they line up (usually) with the periods of periodic table 3 2.5 2 1.5 1 0.5 0 0 10 20 30 40 50 Does this property increase or decrease across a period? 3 2.5 2 1.5 1 0.5 0 0 10 20 30 40 50 Now we are going to look few properties of the elements that exhibit periodic trends 2012 skip to slide 72 ElectronegativityDefinition- the ability of an atom to attract an electron to itself Units - Paulings Background --determined from a hodgepodge of things and was quantified by Linus Pauling. Values range from 0 - 4. With 4 being the most electronegative. Electronegativity the ability of an atom to attract an electron to itself ee+ e- When an atom gets an electron it goes in the outermost shell. The stronger the pull felt on the outer shell from the positive nucleus, the more likely an atom is to attract an electron (more electronegative) atoms get smaller nuclear charge increases shielding is constant Do the noble gases fit this trend? Electronegativity Increases Why do the noble gases NOT fit the trend? Because the have a full valence electron shell (s2 p6) they are very stable as they are and do not want another electron Going DOWN a column: Atoms get larger. Nuclear charge increases BUT Shielding effect increases Electronegativity Decreases going down a column Ionization energy & Electronegativity INCREASE
