Second hourly exam. Monday October 20. 6:45 7:45 pm. Will cover material in lecture notes 9 through 19 inclusive

Size: px

Start display at page:

Download "Second hourly exam. Monday October 20. 6:45 7:45 pm. Will cover material in lecture notes 9 through 19 inclusive"

Roland McLaughlin
5 years ago
Views:

1 Second hourly exam Monday October 20 6:45 7:45 pm Will cover material in lecture notes 9 through 19 inclusive Early exam Monday morning 6:45 7:45 AM 1

2 Orbital energies 1s < 2s < 2p < 3s< 3p < 4s < 3d < 4p <5s < 4d <5p Li 1s 2 2s 1 Li 1s 2 2s 1 1s is a core orbital, 2s is a valence orbital Core orbitals represented by previous noble gas configuraaon Condensed electron configuraaon Li [He] 2s 1

3 Orbital energies 1s < 2s < 2p < 3s< 3p < 4s < 3d < 4p <5s < 4d <5p Electron configuraaon for N N 1s 2 2s 2 2p 3 N 1s 2 2s 2 2p 3 1s is a core orbital, 2s & 2p are valence orbitals Condensed electron configuraaon for N N [He] 2s 2 2p 3

4 Orbital energies 1s < 2s < 2p < 3s< 3p < 4s < 3d < 4p <5s < 4d <5p Electron configuraaon for Cl Cl 1s 2 2s 2 2p 6 3s 2 3p 5 Cl 1s 2 2s 2 2p 6 3s 2 3p 5 1s, 2s, 2p are core orbitals, 3s & 3p are valence orbitals Condensed electron configuraaon for Cl Cl [Ne] 3s 2 3p 5

5 Orbital energies 1s < 2s < 2p < 3s< 3p < 4s < 3d < 4p <5s < 4d <5p Electron configuraaon for V V 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 3 V 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 3 1s, 2s, 2p, 3s, 3p are core orbitals, 4s & 3d are valence orbitals Condensed electron configuraaon for V V [Ar] 4s 2 3d 3

6 Li 1s 2 2s 1 [He]2s 1 Na 1s 2 2s 2 2 p 6 3s 1 [Ne]3s 1 K 1s 2 2s 2 2 p 6 3s 2 3p 6 4s 1 [Ar]4s 1 Rb 1s 2 2s 2 2 p 6 3s 2 3p 6 4s 2 3d 10 4 p 6 5s 1 [Kr]5s 1 Same number of electrons in the same type of valence orbital similar chemistry! 6

7 The periodic table can be used as a guide for electron configuraaons Groups 1A and 2A have the s orbitals filled Groups 3A and 8A have the p orbitals filled Groups 3B- 2B have the d orbitals filled The lanthanides and acanides have the f orbitals filled The period number is the value of n for s and p orbitals the value of n for the d orbitals is the period number minus 1 the value of n for the lanthanides and acanides is the period number minus 2

8 s block elements p block elements d block elements f block elements

9 Electron configuraaon of Cl? Period 3 so valence orbitals have PQN = 3 FiXh column in p block so 5 electrons in 3p orbital Previous noble gas Ne Cl [Ne] 3s 2 3p 5

10 Electron configuraaon of As Period? 4 th pqn of s & p valence orbitals = 4 Column in p block? d electrons? 3 rd yes 3 p electrons 3d orbital Previous noble gas? [Ar] 4s 2 3d 10 4p 3 Ar Unpaired electrons? 3

11 Electron configuraaon of Tellurium? Element number 52 p block period 5 Last orbital filled is a 5p How many electrons in this 5p orbital? Row 4 in p block so 5p 4 d electrons? yes 4d orbital [Kr] 5s 2 4d 10 5p 4 Unpaired electrons? 2

12 Electron configuraaon of Iron? Element number 26 d block Period 4 Last orbital filled is a 3d How many electrons in this 3d orbital? Row 6 in d block so 3d 6 [Ar] 4s 2 3d 6 Unpaired electrons? 4

13 Some excepaons Cu not [Ar] 4s 2 3d 9 but [Ar] 4s 1 3d 10 Ag not [Kr] 5s 2 4d 9 but [Kr] 5s 1 4d 10 Au not [Xe] 6s 2 4f 14 5d 9 but [Xe] 6s 1 4f 14 5d 10 Cr not [Ar] 4s 2 3d 4 but [Ar]4s 1 3d 5 Stability of half or completely filled subshells

14 Electron configuraaon of ions CaAons Remove electron with the highest principal quantum number. If there is more than one subshell available with highest n, remove the electron from the orbital with highest l. Remove electron from a doubly occupied orbital before a singly occupied orbital

15 caaons B 1+ 4 electrons neutral Boron 1s 2 2s 2 2 p 1 B 1+ 1s 2 2s 2 Unpaired electrons?

16 Fe(II) neutral iron [Ar] 4s 2 3d 6 Fe 2+ [Ar] 3d 6 How many unpaired electrons are in Fe(II)? 16

17 Fe(II) neutral iron [Ar] 4s 2 3d 6 Fe 2+ [Ar] 3d 6 How many unpaired electrons are in Fe(II)? 17

18 Fe(III) neutral iron [Ar] 4s 2 3d 6 Fe 3+ [Ar] 3d 5 How many unpaired electrons are in Fe(III)? 18

19 anions Add electrons in accordance with Augau principle Exclusion principle Hund s rule

20 O 2- neutral oxygen 1s 2 2s 2 2 p 4 O 2 1s 2 2s 2 2 p 6 [Ne]

21 P 3- neutral Phosphous [Ne] 3s 2 3p 3 P 3 [Ne] 3s 2 3p 6 [Ar] Unpaired electrons?

22 Periodic properaes Many properaes of the elements depend on their electronic configuraaon This in turn depends on the elements posiaon in the periodic table Size of atoms and ions IonizaAon energy Electron affinity ElectronegaAvity 22

23 Atomic/ionic radius Metals like Cu, ½ of distance between the atomic nuclei in solid d(cu)=256 pm therefore Atomic radius =128 pm

24 Bond length (inter- nuclear separaaon) in gaseous Cl 2 = 198 pm Inter- nuclear separaoon 2r Atomic covalent radius is half of the inter- nuclear separaaon Radius = 198/2 = 99 pm 24

25 Knowing that the covalent radius of Cl is 99 pm we can esamate the radii of other atoms bonded to a Cl atom. 198 pm Cl Cl What is the covalent radius of C? The C- Cl bond length in CH 3 Cl is 176 pm. Therefore the covalent radius of the carbon atom is = 77 pm. H H C H Cl 176 pm

26 Atomic radii trends Li versus Ne Which is larger? Li Ne 3+ nuclear charge electrons 10 decrease 152 pm 70 pm 26

27 As one adds electrons to the same shell the main effect is a contracaon of the size of the electron density because of the increase in nuclear charge decrease size Li [He]2s 1 F [He] 2s 2 2p 5 As one adds electrons to the same subshell shell but increases n, the pqn (the shell) the main effect is a increase in the size of the electron distribuaon increase size F [He] 2s 2 2p 5 I[Kr]5s 2 4d 10 5p 5

[3.3] Energy Level Diagrams and Configurations

[3.3] Energy Level Diagrams and Configurations 1 Energy Level Diagrams Energy level diagrams are used to represent the electron arrangement in an atom 2 Pauli s Exclusion Principle No two electrons have