AP CHEM WKST KEY: Atomic Structure Unit Review p. 1

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1 AP CHEM WKST KEY: Atoic Structure Unit Review p. 1 1) a) ΔE = x J 1 2 nf 1 n 2i = x J = x J b) E = λ hc λ = E hc = (6.626 x J )( x x J 8 ) = x x n = n 1 c x 10 c) c = λν ν = = λ x 10 8 = x (or Hz, your choice) ---OR E x 10 J E = hν ν = = h x 10 J = x c x a) c = λν ν = = λ x 10 8 = x b) E = λ hc E = (6.626 x J )( x x ) = x J ---OR--- E = hν E = (6.626 x J )(1.285 x ) = x J 3. The ignificance of the bright line pectru of an eleent i that each eleent ha a unique line pectru it i often ued to identify eleent. The energy for a given wavelength of light can be found by the equation: E = λ hc Therefore, each wavelength of light ha a pecific aount of energy aociated with it. Furtherore, only certain line how up in the line pectru. If the line are caued by the photon given off by the electron loing energy within the ato, then the electron can only have pecific aount of energy in order to produce thee line. 4. a) Planck howed that the wavelength of light given off by glowing gae have dicrete aount of energy, E = λ hc, intead of having jut any aount of energy. Eintein tated that light i ade up of photon having thee dicrete aount of energy. Furtherore, Eintein howed that energy can be aociated with a with hi equation: E = c 2 Then by cobining Planck equation with thi equation, Eintein indicated that photon could have a a: h =. λc Eintein alo howed that light behave a particle with the photoelectric effect in which light can knock electron off a etal urface.

2 AP CHEM WKST KEY: Atoic Structure Unit Review p. 2 Copton perfored experient in which colliion took place between x-ray and electron and that photon do in fact have the a indicated in Eintein equation. 4. b) de Broglie howed that atter can have wave propertie by howing the relationhip between the a of an object and wavelength: h λ = v where i the a of an object in kg and v i it velocity in /. Alo, experient were carried out that howed that a bea of electron exhibit the ae diffraction pattern a bea of x-ray (diffraction i a wave property) and therefore howed particle having wave propertie. 34 h x 10 J 5. λ = = v 31 8 ( x 10 kg)(0.700)( x 10 ) = 3.47 x Bohr odel of the electron included the following: the electron in a hydrogen ato ove around the nucleu in certain circular orbit (energy level) the electron are quantized the energy of the energy level in Bohr ato increae a the ditance between the nucleu and the energy level increae tated that E n = 0 J and that the energy of the other energy level were uch that the following equation worked for when the electron oved fro one energy level to another (n i the energy level involved) ΔE = x J i nf n Hi theory i upported by the bright line pectru for hydrogen. The ΔE deterined by the above equation atched up perfectly with the energie of the different wavelength of light that appear on thi pectru. 7. Law of phyic include the fact that charged pecie under acceleration will loe energy. In Bohr odel, the electron i under contant acceleration ince it travel in a circular orbit. Thu it hould loe energy and be drawn into the nucleu. Thi doe not happen with table ato. Bohr odel only worked with ato containing one electron. 8. Schrödinger ade the auption that electron travel in oe ort of tanding wave and cae up with the equation Ĥψ = Eψ where ψ i called a wave function. 9. An orbital i a region about the nucleu, having a certain aount of energy, in which an electron ay be found with a 90% probability. It i derived fro the wave function fro Schrödinger equation. 10. Quantu echanic i baed on the 90% probability of electron being in pecific region of the ato. Heienberg Uncertainty Principle i the underlying principle of thi theory. 11. Soething that i quantized in energy can only exit at pecific dicrete aount of energy.

3 AP CHEM WKST KEY: Atoic Structure Unit Review p n principal quantu nuber; repreent energy level; deterine ize of orbital; n = {1,2,3,, } l aziuthal quantu nuber; repreent ublevel; deterine orbital hape; l = {0,,n 1} for all n agnetic quantu nuber; repreent orbital; deterine orbital patial orientation; = { l,,l} for all l pin quantu nuber; repreent electron; deterine electron pin; = {+½, ½} for all 13. n, l,, 1 t e 4, 1, 1, +½ 2 nd e 4, 1, 0, +½ 3 rd e 4, 1, 1, +½ 4 th e 4, 1, 1, ½ The value for for the firt three e can be in any order of 1, 0, and 1. Starting with the fourth e you go back to any of the three value of can equal 1, 0 or 1 for the fourth e. The value for for the firt three e can be either +½ or ½, but all three ut be the ae. Starting with the fourth e, the value of i the one you didn t ue in the firt three. 14. a) 10 b) 2 c) 2 d) a) 64 b) none (ipoible) c) 7 d) a) 10 b) 20 c) a) [Kr] 5 4d c) [Ar] 4 3d 4p b) [Kr] 5 4d 5p d) [Ar] 4 3d 4p 18. all except A a) [Kr] 5 2 4d 3 d) [Kr] 5 1 4d 10 b) [Kr] 5 2 4d 10 5p 6 e) [Rn] 7 2 5f 4 6d 1 c) [Ne] 3 2 3p 6 f) [Xe] 4f 14 5d a) 7 2 b) 4 2 4p 6 4d a) 5 b) 2 c) 8 d) a) n = b) 3p c) 4p d) degenerate both the ae 23. Ca 2+, K +, Cl, S Degenerate orbital are alike in all way except for patial orientation. Thi ean they have the ae hape, ize, energy, etc. Exaple: 3p x, 3p y, 3p z (any orbital in the ae ublevel will be degenerate)

4 AP CHEM WKST KEY: Atoic Structure Unit Review p The 3d and 4d orbital are alike in that they have the ae hape and both can hold up to 2 electron. They are different in that the 4d i larger and ha ore energy than the 3d orbital. 26. a) f b) c) d d) p e) f f) d 27. The aount of repulion between electron depend on the ditance between the electron. Fro the Heienberg uncertainty principle, we can t know preciely the poition of each electron. Thu, we can t know preciely the ditance between the electron to deterine the aount of repulion involved. 28. There i a higher probability of finding the 4 electron cloer to the nucleu than the 3d electron. 29. When ato interact with each other, it will be the valence electron that are involved in thee interaction. Furtherore, how tightly the nucleu hold thee valence electron deterine atoic ize, ionization energy and other propertie of the ato. In other word, the valence electron deterine the cheical propertie of the ato. 30. Eleent in the ae group have iilar propertie becaue they have the ae nuber of valence electron. 31. a) A, ground tate b) P, excited 32. a) 1 b) 2 c) Ca, Mg, Si, Be 34. Cl, S, Br, Li 35. Be, N, Br, F (reeber Be and N are endotheric in thi o do not for table 1- ion) 36. After loing the firt electron, Li ha a noble ga configuration (like He) and i o table that it would take a treendou aount of energy to reove the econd electron. For Be, after loing the firt electron, it can till loe another electron to becoe like He. Therefore, it will take ore energy to reove the econd electron fro Be than it firt electron, but not a uch a it doe for Li. 37. The orbital diagra for N,, how that N i oewhat table already and that any other electron 2 2p added to it will caue extra electron repulion force that cannot be overcoe by the nuclear charge, thu aking the ato untable. For C, the orbital diagra,, how that C can accept another electron without 2 2p exce electron repulion ince it ha an epty orbital in which to accept the electron.

5 AP CHEM WKST KEY: Atoic Structure Unit Review p Generally, adding an electron doen t caue exce repulion force to occur the nuclear charge can handle the extra electron in thi cae and can for a table anion. Therefore, ince the ato i becoing ore table, energy would be releaed to do thi. Every electron added thereafter will caue extra repulion force to occur. Thu, the ato ut gain energy to hold onto thee extra electron. 39. Generally, the aller the ato the ore ionization energy i needed to reove an electron. Since the atoic ize of the ato get aller a one proceed acro the period of the periodic table, the firt ionization energie will increae fro left to right acro the period. A for the light dip in IE between Mg and Al and the dip that occur between P and S, one need to look at the orbital diagra for thee eleent. Mg Al 3 3 3p The Mg ha a filled 3 ublevel therefore a table ublevel. The Al ha only a ingle electron in it 3p ublevel. It will require le energy to reove the ingle 3p electron in Al than to reove one of the electron in Mg 3 ublevel. P S 3 3p 3 3p The configuration for P i quite table with each 3p orbital containing a ingle electron. With the addition of another electron in the 3p ublevel of S, additional repulion force occur between the two electron in the ae orbital. Thu, it would require le energy to reove the additional electron in 3p ublevel of S than to reove an electron fro P 3p ublevel. 40. After an ato loe an electron, the reaining electron ove cloer to the nucleu ince the nuclear charge i now ditributed over fewer electron. Thi ean it would require ore energy to reove the 2 nd electron fro an ato ince the nucleu ha a tighter hold on the electron than when it i neutral. With each ucceive electron reoved, the fewer electron the nuclear charge i ditributed over and therefore ore energy i needed to overcoe the addition attraction between the nucleu and the electron. 41. After Al loe 3 electron, it i like a noble ga (Ne). Therefore, it would require a treendou aount of energy to reove another electron fro a very table ion. A for the gap between the 1 t, 2 nd and 3 rd ionization, each tie Al loe an electron, it nucleu bind the reaining electron tighter to the nucleu. Thu it will require ore energy to reove the next electron fro the cation, but none nearly a uch a it would to reove the 4 th electron fro thi ato. 42. nonetal F etal Fr 43. The atoic ize decreae a you go acro the period (left to right) due to the increaed nuclear charge having a tighter hold on electron that are all in the ae energy level. The atoic ize increae a you go down the group due to larger energy level being occupied and increaed hielding effect of the core electron on the valence electron. 44. The etal on the left ide of the periodic table have low ionization energie. Thi allow thee ato to ore eaily loe electron to for ion and be involved in cheical reaction. The nonetal to the right ide of the periodic table have a higher electronegativity. Thi allow the to ore eaily gain electron to for ion and be involved in cheical reaction. 45. The nonetal are typically aller than etal. Thi ean ore IE i needed to reove electron. Alo, it ean the nonetallic ato are ore apt to gain electron (ore exotheric electron affinity and higher electronegativity) ince electron outide the ato are cloer to the nucleu in thee ato than for etallic ato.

6 AP CHEM WKST KEY: Atoic Structure Unit Review p O 2 Na 47. larget: Se 2- allet: Sr Metal are reducing agent becaue they have lower ionization energie and can eaily loe electron (oxidize). By doing thi, they caue another ubtance to gain electron and are therefore reducing agent. Nonetal are oxidizing agent ince they have high electronegativitie and can eaily gain electron (reduce). By doing thi, they caue another ubtance to loe electron and are therefore oxidizing agent. 49. Fr > C > Rb > K > Na > Li Thi order i the revere order of increaing firt ionization energie for thee eleent. The lower the ionization energy, the ore reducing power the eleent ha. 50. A you go down the group, the: denity generally increae (except K i le than Na) elting point decreae boiling point generally decreae (C i higher than Rb) firt ionization energy decreae atoic ize increae ionic ize increae 51. -the a of the particle the heavier the particle the le it can be bent -the velocity of the particle the fater the particle the le it can be bent -the electric charge of the particle the higher the charge the ore it can be bent -the trength of the agnet the tronger the agnet the ore the bea can be bent -the aount of charge in the plate the tronger the charge the ore the bea can be bent plu the bea will ove in the direction of the oppoitely charged plate 52. below threhold frequency: no electron eitted regardle of light intenity -greater than threhold frequency: nuber of electron eitted increae with light intenity -greater than threhold frequency: kinetic energy of eitted electron increae linearly with the frequency of light 53. a) John Dalton b) JJ Thoon c) JJ Thoon d) Robert Millikan e) Henri Becquerel f) Ernet Rutherford g) Jae Chadwick h) Robert Millikan

Chemistry I Unit 3 Review Guide: Energy and Electrons

Chemistry I Unit 3 Review Guide: Energy and Electrons Cheitry I Unit 3 Review Guide: Energy and Electron Practice Quetion and Proble 1. Energy i the capacity to do work. With reference to thi definition, decribe how you would deontrate that each of the following