Ch. 6 Electronic Structure and The Periodic Table

Transcription

1 Ch. 6 Eectronic tructure and The Periodic Tabe 6-: Light, Photon Energies, and Atoic pectra. The Wave Nature of Light: Waveength and Frequency. The partice Nature of Light; Photon Energies 3. Atoic pectra 6-: The Hydrogen Ato 氫原子模型. Bohr Mode. Quantu Mechanica Mode 6-3: Quantu Nuber 量子數. First Quantu Nuber, n; Principa Energy Leves. econd Quantu Nuber, ; ubeves(s, P,d,f) 3. Third Quantu Nuber, ; Orbitas 4. Fourth Quantu Nuber, M s : Eectron pin 5. Paui Excusion Principe 6-4: Atoic Orbitas; hapes and ize 6-5: Eectron Configurations in Atos. Eectron Configuration fro ubeve Energies. Fiing of ubeves and the Periodic Tabe 3. Eectron Configuration fro the periodic Tabe 6-6: Orbita Diagras of Atos 6-7: Eectron Arrangeents in Monatoic Ions. Ions with Nobe-Gas tructures. Transition Meta Cations 6-: Periodic Trends in the Properties of Atos. Atoic Radius. Ionic Radius 3. Ionization Energy 4. Eectronegativity

2 Ch. 6 Eectronic tructure and The Periodic Tabe Ch. 原子構造 : 原子核 : 中子 + 質子外圍 : 電子 Ch 6. 電子的結構 energy eves, orbitas. 6- Light, Photon energies, and Atoic pectra The wave nature of ight: waveength ( ) and frequency(ν ) Light traves trough space as a wave. Waves have three priary characteristics. Fig 6.: Characteristics of waves. () Waveength : The distance between two consecutive crests or troughs. (n) () Frequency ν : The nuber of wave cyces that pass a given point in unit tie. ( s ; Hz) (3). Apitude ψ : The height of a crest or the depth of a trough. 唸 psi ν c c : the speed of ight in a vacuu.99 0 s Ex 6.: You sit in your back yard on a war suer evening watching the red sky ( 65 n) at sunset and istening to usic fro your CD payer. The aser in the atter has frequency 3.4 x 0 4 s -. (a) What is the frequency of the radiation fro the red sky? (b) What is the wave ength of the aser in n? Ans:

3 ( a) ν ν c 9 7 ; 65 n c.99 0 s s Hz (b) c ν.99 0 s s n Fig 6.:The eectroagnetic spectru. Visibe ight 紫外線 uv 400 ~ 700 n 紅外線 IR (utravioet) 紫 紅 (infrared) The partice nature of ight, photon energies : Max Panck:backbody radiation Abert Einstein:photo eectric effect Light generates a strea of partices caed photons, whose energy is given as: E h ν hc 34 h:panck s constant J s Ex 6.: odiu vapor ap are coony used to iuinate highways because of their intense yeow-orange eissions at 59 n. (a) Cacuate the energy, in joues, of one photon of this ight. 3

4 Ans: (b) Cacuate the energy, in kiojoues, of one oe of such photons. (c) To sense visibe ight, the optic never needs at east.0x0-7 J of energy to trigger ipuses that reach the brain. How any photons of the sodiu ap eissions are needed to see the yeow ight? hc (b) E photon 000 J o 34 ( ) (.99 0 ) 9 ( a) E J 7 (c) n J kj photons 03 kj J 9 J photon 59 photons J Atoic pectra Isaac Newton: The visibe ight fro the sun can be broken down into its various coor coponents by a pris. The spectru obtained is continuous. 400 ~ 700 n High energy of gaseous eeents: The spectru consist of discrete ines given off at specific waveengths. 每一元素 ( 氣態 ) 均有特定光譜, 可用以鑑定其種類. Na: 59.0 n and 59.6 n ( 黃光 ) 用途 : 高速公路 Na 蒸氣燈 hc E h ν Photons are produced when an eectron oves fro one energy eve to another. 低能階 高能階 ; 吸收能量 E 高能階 低能階 ; 釋放能量 E + 4

5 6- The hydrogen ato 93 Nies Bohr (9 Nobe Prize in physics) Bohr ode: Bohr s equation: RH En E n :energy of eectron; J. n R H: Rydberg constant.0 0 J n: principa quantu nuber. Zero energy: The proton and eectron are copetey separated. 即 n 0 E E n 值. n ground state, 其餘 n > 為 excited state. 3. When an excited eectron gives off energy as a photon of ight, it drops back to a ower energy state. n n : E R ( ) H n n hv v RH n n R H h n n R H.0 0 J 34 h J R H h Hz Tabe 6.: 由 n hi n 0 釋出能量, 放出光子 n 0 Lyan series; uv n 0 Baer series; visibe ight n 0 3 Paschen series; IR n 0 4 Brackett n 5 Pfund 0 5

6 Ex 6-3:Cacuate the waveength in nanoeters of the ine in the Baer series that resuts fro the transition n 4 n. Ans: E R H n n J 4 hc E hν J n or v R H h n n v C n 4 Hz Quantu echanica ode 量子力學模型 Bohr hydrogen ode: Highy successfu ony 0. % error. Appy on heiu: 5 % error, 不適用 An eectron oving about the nuceus in a we-defined orbit at a fixed distance fro the nuces had to be abandoned. 94 法國人. Louis de Brogie 提出 : If ight coud show the behavior of partices (photons) as we as wave, then perhaps an eectron which Bohr had treated as a partice, coud behave ike a wave. wave echanics 波動力學 quantu echanics 量子力學 Quantu echanics 與 Bohr hydrogen ode 不同處 :. The kinetic energy of an eectron is inversey reated to the voue of the region 6

7 to which it is confined. 電子接近原子核時 eectrostatic energy decreases 趨於安定則電子可能全掉入原子核內, 但實際並非如此, 因為同時會發生動能上升, 造成彼此牽制 當達平衡時原子最穩定. It is ipossibe to specify the precise position of an eectron in an ato at a given instant. 唯一可行的是估計在特定區域內, 電子出現的機率. 6 Erwin chrodinger Wave properties of an eectron in an ato d ψ π ( E v) + ψ 0 dx h ψ : apitude wave function ψ is directy proportiona to the probabiity of finding the eectron at a particuar point. Fig 6.4 :The eectron distribution in the ground state of hydrogen ato. 顏色愈深, 發現電子之機率愈大 6-3 Quantu nubers ψ 與 quantu nubers 相關聯 n,,, energy of the orbit; shape; orientation in space; eectron spin direction Each eectron in an ato has a set of four quantu nubers: 7 n,,., First quantu nuber, n, principa quantu nuber 主量子數 ; principa energy eves 主能階

8 It represents the ain energy eves for the eectron or shes, and can be thought of a she in the space where the probabiity of finding an eectron with a particuar vaue n is high. n n energy eve. n, deterine the energy of an eectron. n 電子之能量 n 為正整數,, 3, 4, 5, 6, 7 ( 目前至 7) econd quantu nuber,, anguar quantu nuber 角量子數 subeves (s, p, d, f, g, h ) 軌域 This quantu nuber specifies subenergy eves within the ain energy eves (sub-she) where the probabiity of finding an eectron is high if that energy eve is occupied. Each principa energy eve incudes one or ore subeves. 符號 : The genera shape of the eectron, arger vaues of produce ore copex shape. 例 n 4 0,,, 3 (n ) four subeves. nth principa eve, there are n different subeves. Type of subeve s p d f 能量 : ns < np < nd < nf Third quantu nuber,, agnetic quantu nuber 磁量子數 orbitas 副軌域 Each subeve contains one or ore orbitas, which differ fro one another in the vaue assigned to the third quantu nuber,. Deterine the direction in space of the eectron coud surrounding the nuces. 次軌域 副軌域 -,,-,0,,, 共 ( +) 個 orbitas

9 n 4, 0,,, , 0, -, -, 0,, 3-3, -, -, 0,,, 3 orbita - s 3 orbitas - p 5 orbitas - d 7 orbitas - f s 有一個副軌域,p 有三個副軌域 d 有五個副軌域,f 有七個副軌域 Fourth quantu nuber,, eectron spin quantu nuber. Associated with eectron spin, cockwise and countercockwise + Paui excusion principe 包立不相容定理 No two eectrons in an ato can have the sae set of four quantu nubers. Ex 6-4: Consider the foowing sets of quantu nubers ( n,,, ). Which ones coud not occur?for the vaid sets identify the orbita invoved. Ans: a) 3,, 0, + 3p b),, 0, 0,,(n ), n, 0 不存在 c), 0, 0, + s d) 4, 3,, + 4f 9

10 e),, 0, 0 + or 不存在 Ex 6.5: (a) What is the capacity for eectrons of an s subeve?a p subeve?a d subeve?a f subeve? (b) What is the tota capacity for eectrons of the fourth principa eve? Ans: a). s 軌域 0 0 p 軌域 d 軌域 f 軌域 3 -, 0, + + or -, -, 0, +, + 個電子 + or -3,-, -, 0, +, +, 個電子 + or 5 0 個電子 + or 7 4 個電子 b). n 4 0 s 軌域含 個電子 p 軌域含 6 個電子 d 軌域含 0 個電子 3 f 軌域含 4 個電子共 3 個 n 個 ~ C-. G 0 E? 0