Camp 1 - chem.latech.edu

Camp 1 - chem.latech.edu

Chemistry 481(01) Spring 2017 Instructor: Dr. Upali Siriwardane e-mail: [email protected] Office: CTH 311 Phone 257-4941 Office Hours: M,W 8:00-9:00 & 11:00-12:00 am; Tu,Th, F 9:30 - 11:30 a.m. April 4 , 2017: Test 1 (Chapters 1, 2, 3, 4) April 27, 2017: Test 2 (Chapters (6 & 7) May 16, 2016: Test 3 (Chapters. 19 & 20) May 17, Make Up: Comprehensive covering all Chapters Chemistry 481, Spring 2017, LA Tech Chapter-1-1 Origin of Elements in the Universe Scientists have long based the origin of our Universe on the Big Bang Theory. According to this theory, our universe was simply an expanding fairly cold entity consisting of only Hydrogen and Helium during it's incipient stages. Over the expanse of many years, and through a continuing process of fusion and fission, our universe has come to consist of numerous chemical elements, four terrestrial planets(Earth, Mars, Venus, and Mercury), and five giant gas planets(Saturn, Jupiter, Neptune, Pluto, and Uranus).

Chemistry 481, Spring 2017, LA Tech Chapter-1-2 Predicted Nuclear Fusion of Light Elements in the Young, Hot Universe Chemistry 481, Spring 2017, LA Tech Chapter-1-3 Few minutes after big Bang Chemistry 481, Spring 2017, LA Tech Chapter-1-4 Eight Steps in the History of the Earth 1. The Big Bang 2. Star Formation 3. Supernova Explosion 4. Solar Nebula Condenses 5. Sun & Planetary Rings Form 6. Earth Forms

7. Earth's Core Forms 8. Oceans & Atmosphere Forms Chemistry 481, Spring 2017, LA Tech Chapter-1-5 Nuclear Burning Chemistry 481, Spring 2017, LA Tech Chapter-1-6 Origin of the Elements: Nucleosynthesis Elements formed in the universe's original stars were made from hydrogen gas condensing due to gravity. These young stars "burned" hydrogen in fusion reactions to produce helium and the hydrogen was depleted. Reactions such as those below built up all the heavier elements up to atomic number 26 in the periodic table. When the stars got old they exploded in a super nova, spreading the new elements into space with

high flux of neutrons to produce heavy elements by neutron capture. Chemistry 481, Spring 2017, LA Tech Chapter-1-7 1. What are the two basic types of nuclear reactions? Give examples of each that occur during the formation of the Universe Chemistry 481, Spring 2017, LA Tech Chapter-1-8 Cosmic Abundances Chemistry 481, Spring 2017, LA Tech Chapter-1-9 Balancing Nuclear Reactions Two conditions must be met to balance nuclear reactions: 1. The sum of the masses of the reactants must equal the sum of the masses of the products. (i.e., the values

of A must balance on both sides of the equation.) 2. The sum of the protons for the reactants must equal the sum of the protons for the products. (i.e., the values of Z must balance on both sides of the equation.) Chemistry 481, Spring 2017, LA Tech Chapter-1-10 Balancing Nuclear Reactions 2. Complete the following Nuclear reactions: a) Uranium 238 decays by alpha radiation to produce what other element? b) Uranium 238 decays by alpha radiation to produce what other element? c) What element did we start out with if the result of beta decay is bismuth 214? Chemistry 481, Spring 2017, LA Tech Chapter-1-11

Balancing Nuclear Reactions 2. Complete the following Nuclear reactions: d) What element is produced when mercury 201 captures an inner shell electron with the production of a gamma ray to release excess energy? Chemistry 481, Spring 2017, LA Tech Chapter-1-12 3. Predict the most likely modes of decay and the products of decay of the following nuclides: 17 F: Ag: 105 Ta: 185 Chemistry 481, Spring 2017, LA Tech

Chapter-1-13 Bonding Energy Curve Chemistry 481, Spring 2017, LA Tech Chapter-1-14 Nuclear Binding Energy The binding energy of a nucleus is a measure of how tightly its protons and neutrons are held together by the nuclear forces. The binding energy per nucleon, the energy required to remove one neutron or proton from a nucleus, is a function of the mass number A. (Dm) mass defect (Dm) = Mass of Nuclide - mass of (p + n +e ) Proton mass: 1.00728 amu Neutron mass: 1.00867 amu Electron mass: 0.00055 amu Massdefect (Dm), then multiply by 931.5 MeV/amu Chemistry 481, Spring 2017, LA Tech Chapter-1-15 4. Using the binding energy calculator, calculate the

binding energy 235U if the mass of the this nuclide (isotope) is 235.0349 amu. ( P= 1.007277 amu, N= 1.008665 amu, e- =0.0005438 amu ) Chemistry 481, Spring 2017, LA Tech Chapter-1-16 5. What are theories that have been used to describe the nuclear stability? Chemistry 481, Spring 2017, LA Tech Chapter-1-17 Stability of the Elements and Their Isotopes P/N Ratio Why are elements With Z > 82 are Unstable? Chemistry 481, Spring 2017, LA Tech Chapter-1-18

Magic Numbers Nuclei with either numbers of protons or neutrons equal to Z, N =2 (He), 8(O), 20 (Ca), 28(Si), 50(Sn, 82(Pb), or 126(?)(I) exhibit certain properties which are analogous to closed shell properties in atoms, including anomalously low masses, high natural abundances and high energy first excited states. Chemistry 481, Spring 2017, LA Tech Chapter-1-19 The Kinetics of Radioactive Decay Nuclear reactions follow 1st order kinetics Chemistry 481, Spring 2017, LA Tech Chapter-1-20 6. How long would it take for a sample of 222Rn that weighs 0.750 g to decay to 0.100 g? Assume a halflife for 222Rn of 3.823 days?

Chemistry 481, Spring 2017, LA Tech Chapter-1-21 7. The skin, bones and clothing of an adult female mummy discovered in Chimney Cave, Lake Winnemucca, Nevada, were dated by radiocarbon analysis. How old is this mummy if the sample retains 73.9% of the activity of living tissue? Chemistry 481, Spring 2017, LA Tech Chapter-1-22 Bohr model of the atom Balmer later determined an empirical relationship that described the spectral lines for hydrogen. DE = - 2.178 x 10- nf = 2 18

m -1 = ( 1 2 nf - ) 1 2 ni ni = 3,4, 5, . . . Blamer series Spectra of many other atoms can be described by similar relationships.

Chemistry 481, Spring 2017, LA Tech Chapter-1-23 Bohr model of the atom The Bohr model is a planetary type model. Each principal quantum represents a new orbit or layer. The nucleus is at the center of the model. RH = 2.178 x 10-18 J Chemistry 481, Spring 2017, LA Tech En = RH En = - Chapter-1-24 Emission Spectrum of Hydrogen

Bohr studied the spectra produced when atoms were excited in a gas discharge tube. He observed that each element produced its own set of characteristic lines. Chemistry 481, Spring 2017, LA Tech Chapter-1-25 Emission Spectrum of Hydrogen Line Spectrum Energy is absorbed when an electron goes from a lower(n) to a higher(n) Energy is emitted when an electron goes from a higher(n) to a lower(n) level Energy changed is given by:DE = Ef - Ei or DE = -2.178 x 10-18 [1/n2f - 1/n2i] J DE is negative for an emission and positive for an absorption DE can be converted to l or 1/ l by l = hc/E. Chemistry 481, Spring 2017, LA Tech Chapter-1-26

What is Bohrs Atomic model? explain emission spectrum of hydrogen atom applied the idea of Quantization to electrons to orbits energies of these orbits increase with the distance from nucleus. Energy of the electron in orbit n (En): En = -2.178 x 10-18 J (Z2/n2) En = -2.178 x 10-18 J 1/n2; Z=1 for H Chemistry 481, Spring 2017, LA Tech Chapter-1-27 Bohr model of the atom Balmer later determined an empirical relationship that described the spectral lines for hydrogen. En = DE = - 2.178 x 10 nf = 2

-18 J - ( 1 2 nf - 1 2 ni ) ni = 3,4, 5, . . . Blamer series Spectra of many other atoms can be described by similar relationships.

Chemistry 481, Spring 2017, LA Tech Chapter-1-28 Paschen, Blamer and Lyman Series Chemistry 481, Spring 2017, LA Tech Chapter-1-29 Calculation using the equation: E = -2.178 x 10-18 (1/nf2 - 1/ni2 ) J, Calculate the wavelength of light that can excite the electron in a ground state hydrogen atom to n = 7 energy level. Chemistry 481, Spring 2017, LA Tech Chapter-1-30 Calculation using Bohr eqaution The energy for the transition from n = 1 to n = 7: DE = -2.178 x 10-18 J [1/n2f - 1/n2i]; nf = 7, ni = 1 DE = -2.178 x 10-18 [1/72 - 1/12] J DE = -2.178 x 10-18 [1/49 - 1/1] J

DE = -2.178 x 10-18 [0.02041 - 1] J DE = -2.178 x 10-18 [-0.97959] J = 2.134 x 10-18 J (+, absorption) calculate the l using l = hc/E 6.626 x 10-34 Js x 3.00 x 108 m/s l = ---------------------2.13 x 10-18 J l = 9.31 x 10-8 m Chemistry 481, Spring 2017, LA Tech Chapter-1-31 8. Using Bohr energy calculator, calculate the wavelength of light that can excite the electron in a ground state hydrogen atom from n = 5 to n = 3 energy level. Chemistry 481, Spring 2017, LA Tech Chapter-1-32 Wave theory of the electron 1924: De Broglie suggested that electrons

have wave properties to account for why their energy was quantized. He reasoned that the electron in the hydrogen atom was fixed in the space around the nucleus. He felt that the electron would best be represented as a standing wave. As a standing wave, each electrons path must equal a whole number times the wavelength. Chemistry 481, Spring 2017, LA Tech Chapter-1-33 De Broglie waves De Broglie proposed that all particles have a wavelength as related by: l = l h m v

Chemistry 481, Spring 2017, LA Tech = = = = h mv wavelength, meters Planks constant mass, kg frequency, m/s Chapter-1-34 Constructively Interfered 2D-Wave Chemistry 481, Spring 2017, LA Tech Chapter-1-35 destructively Interfered 2D-Wave

Chemistry 481, Spring 2017, LA Tech Chapter-1-36 Two-dimensional wave - Vibrations on a Drumskin One circular node (at the drumskin's edge) Two circular nodes (one at the drumskin's edge plus one more) Three circular nodes (one at the drumskin's edge plus two more) One transverse node (plus a circular one at the drumskin's edge) Two transverse nodes (plus one at the drumskin's edge) Chemistry 481, Spring 2017, LA Tech Chapter-1-37

What is a wave-mechanical model? motions of a vibrating string shows one dimensional motion. Energy of the vibrating string is quantized Energy of the waves increased with the nodes. Nodes are places were string is stationary. Number of nodes gives the quantum number. One dimensional motion gives one quantum number. Vibrating String : y = sin(npx/l) d2y/dx2 = -(n2p2/l2)sin(npx/l) = -(n2p2/l2)y Chemistry 481, Spring 2017, LA Tech Chapter-1-38 Quantum model of the atom Schrdinger developed an equation to

describe the behavior and energies of electrons in atoms. His equation ( Wave function y) is similar to one used to describe electromagnetic waves. Each electron can be described in terms of Wave function yits quantum numbers. yn, l, ml, ms), y2is proportional probablity of finding the electron in a given volume. Max Born Interpretation: y2= atomic orbital Chemistry 481, Spring 2017, LA Tech Chapter-1-39 Schrdinger Equation y = wave function E = total energy V = potential energy Chemistry 481, Spring 2017, LA Tech

Chapter-1-40 Schrdinger Equation y = wave function E = total energy V = potential energy Chemistry 481, Spring 2017, LA Tech Chapter-1-41 Schrdinger Equation in Polar Coordinates Chemistry 481, Spring 2017, LA Tech Chapter-1-42 Polar Coordinates Chemistry 481, Spring 2017, LA Tech Chapter-1-43 Quantum Model of atom Electrons travel in three dimensions Four quantum numbers are needed three to describe, x, y, z, and four for the spin

four quantum numbers describe an orbital currently used to explain the arrangement, bonding and spectra of atoms. Chemistry 481, Spring 2017, LA Tech Chapter-1-44 Four Quantum Numbers of the Atom n value could be 1, 2, 3, 4, 5, 6. 7. . . etc. l values depend on n value: can have 0 . . . (n - 1) values ml values depends on l value: can have -l . , 0 . . . +l values of ml ms values should always be -1/2 or +1/2 Chemistry 481, Spring 2017, LA Tech Chapter-1-45 Solutions to Shrdinger Equation

Series of allowed discrete y values: yn, l, ml, ms n = 1,2,3,4,5,6,7..etc. En = - Chemistry 481, Spring 2017, LA Tech Chapter-1-46 Components of y Mathematical expression of hydrogen like orbitals in polar coordinates: Radial yn, l, ml, ms (r,,) = R n, l, (r) Y l, ml, (,) R n, l, (r ) = Radial Wave Function Angular Y l, ml, (,) =Angular Wave Function

[R n, l (r )]2 Chemistry 481, Spring 2017, LA Tech or 4pr2R2 = Radial Distribution Function or Pnl(r). Chapter-1-47 Radial Distribution Function, Pnl(r). This is defined as the probability that an electron in the orbital with quantum numbers n and l will be found at a distance r from the nucleus. It is related to the radial wave function by the following relationship: ; normalized by Chemistry 481, Spring 2017, LA Tech Chapter-1-48 9. Describe the Schrdinger equation and the breaking up of wave function, y into radial and

angular component of a wave function and explain the general rule used to find the number of radial and angular nodes of a wave function. Chemistry 481, Spring 2017, LA Tech Chapter-1-49 s-Atomic Orbitals R n, l, (r) only no Y l, ml, (,) s orbitals Chemistry 481, Spring 2017, LA Tech Chapter-1-50 2s-Atomic Orbital: Probability distribution 2 for the 2s orbital 2s orbital Chemistry 481, Spring 2017, LA Tech Chapter-1-51 s-Atomic orbitals

2s 3s Chemistry 481, Spring 2017, LA Tech Chapter-1-52 p-Atomic orbitals 2p 3p Chemistry 481, Spring 2017, LA Tech Chapter-1-53 Nodes in the y Total nodes = n -1 Angular nodes = l Radial nodes = n -1- l Eg 4d orbital: Total nodes = 4 -1 = 3 Angular nodes = l = 2 Radial nodes = n -1- l = 4-1-2 = 1

Chemistry 481, Spring 2017, LA Tech Chapter-1-54 R n, l, (r ) = Radial Wave Function Chemistry 481, Spring 2017, LA Tech Chapter-1-55 10. Consider the following radial probability density-distribution plot and respond to the associated questions. a) How many radial nodes are there? b) If the total number of nodes is 3, what type of orbital is involved? c) Which orbital would it be if there were one more node? Chemistry 481, Spring 2017, LA Tech Chapter-1-56 R (r)

P (r) n Radial wavefunctions, Rnl(r), and the radial distribution functions, Pnl(r) l nl nl 1s 1s 1 0 2s 2s 2 0

2p 2p 2 1 3s 3s 3 0 3p 3p 3 1

3d 3d 3 2 Chemistry 481, Spring 2017, LA Tech Chapter-1-57 d-orbitals 2 2 2 (dxy, dxz, dyz, dz , and dx -y orbitals) Chemistry 481, Spring 2017, LA Tech Chapter-1-58 f-orbitals ( 4fy3 , 4fx3 , 4fz3 , 4fxz2y2 , 4fyz2x2 , 4fzx2y2 , and 4fxyz orbitals)

Chemistry 481, Spring 2017, LA Tech Chapter-1-59 Screening (shielding) constant ()) Screening (shielding) constant ()) for each electron is calculated based on: the principle quantum number orbital type and penetration and of all other electrons in an atom. ) gives Zeff . Zeff = Z - ); Z is the atomic number. Chemistry 481, Spring 2017, LA Tech Chapter-1-60 Effective nuclear charge (Zeff) Zeff is the nuclear charge felt by an electron in a multielectron atom: a) Each electron in an atom has different Zeff. b) Each Zeff is less than atomic number (Z) since electrons screen each other from the nucleus. c) Zeff depends on the n and l quantum number of an electron.

d) Zeff Depends on orbital type the electron is in: Z eff of 4s > 4p > 4d > 4f. Chemistry 481, Spring 2017, LA Tech Chapter-1-61 Radial Wave Funtions Chemistry 481, Spring 2017, LA Tech Chapter-1-62 Radial Distribution Functions, Penetration and Shielding Chemistry 481, Spring 2017, LA Tech Chapter-1-63 Penetration & Shielding of an Electron in Multi-electron Atom Penetration of an electron: Greater the penetration there is more chance of electrons being located close to the nucleus. Comparing s, p, d, or f orbitals within same shell (or

principle QN), penetration of an electrons are in the order: s > p > d > f Shielding power of an electron: Shields of other electrons depends penetration and the orbital type. Shielding power of electrons in orbitals of that same shell are: s > p > d > f Chemistry 481, Spring 2017, LA Tech Chapter-1-64 Slater Calculation of (Zeff) Chemistry 481, Spring 2017, LA Tech Chapter-1-65 Slater Calculation of (Zeff) Chemistry 481, Spring 2017, LA Tech Chapter-1-66 11. Cu: (1s2)(2s2, 2p6) (3s2,3p6) (3d10) (4s1) : there

are two possible scenarios for forming Cu+ ionionizing 3d10 electron or 4s1. Using Slaters Rules show which one of the electrons 4s or 3d would come out easily. If the electron is in a d or f-orbital: All electrons in groups higher than the electron in question contribute zero to s. Each electron in the same group contributes 0.35 to s. All those in groups to the left contribute 1.0 to s (n-3) (n-2) (n-1) (n-1) Cu: (1s2)(2s2, 2p6) (3s2,3p6) (3d10) (4s1) s(4s1) = ( 10x1 ) ( 8x 0.85)(1X10) = 26.8 Zeff = 29 26.6 = 2.4 Cu: (1s2)(2s2, 2p6) (3s2,3p6) (3d10) (4s1) s(3d1) = ( 18x1 ) ( 9x 0.35) (0) = 21.15 Zeff = 29 21.15 = 7.85 Chemistry 481, Spring 2017, LA Tech Chapter-1-67

Effective nuclear charge (Zeff) of Atomic Orbitals vs. Z (atomic number) En = Chemistry 481, Spring 2017, LA Tech - Chapter-1-68 How do you get the electronic configuration of an atom? Use periodic table Periodic table is divided into orbital blocks Each period: represents a shell or n Start writing electron configuration Using following order 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d (building up (Auf Bau) principle:) Chemistry 481, Spring 2017, LA Tech Chapter-1-69

ELECTRONIC CONFIGURATION OF MANY-ELECTRON ATOMS AUFBAU (GER. BUILDING UP) PRINCIPLE PAULI EXCLUSION PRINCIPLE HUNDS RULE Chemistry 481, Spring 2017, LA Tech Chapter-1-70 Electronic Confn Li Be 1 2s 2 2s Na

Mg 1 3s 2 3s Sc K Ca 1 4s 2 4s Rb Sr 3d

1 2 4s Y 1 5s 2 5s 4d 1 Lu2 5s 14 Cs

Ba 4f 1 6s 2 6s 5d 1 Lr2 Fr Ra 1 7s 2

7s 6s 6d Ti 3d 2 3d 2 4s 4d 2 4d 5s 5d

2 Ac2 3 6s 2 6s 1 4f 5d 1 Th 1 2 6s2 6f 2

Chemistry 481, Spring 2017, LA Tech 7s 2 7s 6d 5 6 7 8 5 3d 2 4s 2 4s

Tc 4d 3d 2 4s Ru 5 4d Rh 7 4d W1 Re 2

Os 1 14 14 14 4f Ce 1 5 5s 14 5d 2

La 6s 5d 4f Ni 3d 5d 5s 4 4f 5d 2 Pr 6s 3

5 5d 2 Nd 6s 4 5s 6 2 Pm 6s 5 4f U 4f Np

2 6s2 5f 2 6s3 5f 2 6s4 5f 1 2 7s 6d 1 2 7s 6d

4f 14 5d 4f Pa 6d 8 Ir1 5s 4f C N O

F Ne 2 2s 2 2s 2 2s 2 2s 2 2s 2 2s 2p

Co 4d 5s 14 2 1s Fe Mo Ta2 1 1s Mn 1 4s

3 He Cr 3d Nb Hf2 4f 3 2 4s Zr 1 2 7s

V H B 1 2 7s 7 2 Sm 6s 4f 6 Pu 2 6s 5f

6 2 7s 3d Cu 3d 2 4s 1 4s 4d 10 Pt 4f 10

Gd 7 1 6s 7 4f Cm 1 Am 2 6s 7 2 7s 5d 7 5f 2 6s

6d 10 1 2 7s 4f Al Si 2 3s 2 3s 2 3s Ga

1 Ge2 3d 10 3p 3d 10 2 2 4p10 4d 3 4p10 4d 2

1 5p10 5d 10 2 6s 9 2 1 4p10 4d 14 4f 10 4s Sb

5s Pb 2 Tb 6s As3 3p 3d 1 Dy 6p 4f 10 2p 4

S 4s Sn Tl 5d P In 2 5s 5s 14 5d 1 Eu

6s 5f 4f 4d Hg 2 5s 9 4f 10 Au 1 14 5d

4d Cd 3 2p 2 4s 2 4s Ag Pd 3d 10 2

2p 3p Zn 10 1 2 5s 2 3s Se4 3p 3d 10 4f

12 2 2 6s 2 6s 2 6s 4 Tm 6p 4f 13 10 11

12 13 2 7s 2 7s 2 7s 2 7s 2 6 5p10 5d 9

5f 2 5s 2 5 5p10 5d Md 2 5f 10 4 5p10 5d Fm 2

5f 3d 5s Rn Es2 6s 5f 10 At Cf2 6s 6s 3d Kr6

3p 6 4p10 4d Bk 2 6s Br5 3p 5 4p10 4d 2 6s 11 2 3s

4 4p10 4d 2 6s 4f 2 3s Ar 4s Xe 3 5p10 5d 3 Er

Cl I 2 5p10 5d 6p 6 2p 2 4s Te 5s Po 2 Ho

5 2 4s Bi 6p 2p 6s 5f 5 Yb 6p 4f 14 No

2 6s 5f 14 2 2 Chapter-1-71 7s 7s 6p 6 Using the periodic table To write the ground-state electron configuration of an element: Starting with hydrogen, go through the elements in order of increasing atomic number As you move across a period

Add electrons to the ns orbital as you pass through groups IA (1) and IIA (2). Add electrons to the np orbital as you pass through Groups IIIA (13) to 0 (18). Add electrons to (n-1) d orbitals as you pass through IIIB (3) to IIB(12) and add electrons to (n-2) f orbitals as you pass through the f -block. Chemistry 481, Spring 2017, LA Tech Chapter-1-72 Writing electron configurations Electron configurations can also be written for ions. Start with the ground-state configuration for the atom. For cations, remove a number of the outermost electrons equal to the charge. For anions, add a number of outermost electrons equal to the charge. Chemistry 481, Spring 2017, LA Tech

Chapter-1-73 Exception to Building Up Principle a) Electronic Configuration of d-block and f- block elements d5 or d10 and f7 or f14 are stable Cr :[Ar] 3d4 4s2 wrong Cr :[Ar] 3d5 4s1 correct Cu :[Ar] 3d9 4s2 wrong Cu :[Ar] 3d10 4s1 correct Chemistry 481, Spring 2017, LA Tech Chapter-1-74 Lanthanoids Ce La 5d 1

2 6s 4f 1 5d 1 2 6s Gd Pr 4f 3 2 6s Chemistry 481, Spring 2017, LA Tech

Nd Pm Sm Eu 4f 4 2 6s 4f 5 2 6s 4f 6 2 6s 4f

7 2 6s 4f 7 5d 1 2 6s Tb 4f 9 2 6s Dy Ho

Er Tm Yb 10 11 12 13 14 4f 4f 4f 4f 4f 2 6s 2 6s 2 6s 2 6s

Chapter-1-75 6s 2 Actinoids Pa Ac Th 1 2 6d 2 7s 6f 2

7s 5f 2 6d 1 2 7s Chemistry 481, Spring 2017, LA Tech U 5f 3 6d 1 2

7s Np 5f 4 6d 1 2 7s Cm Pu Am 5f 6 2 7s 7 5f

2 7s 5f 7 6d 7s 1 2 Bk 5f 9 2 7s Cf Es

Fm Md No 10 11 12 13 14 5f 5f 5f 5f 5f 2 7s 2 7s 2 7s 2 7s

Chapter-1-76 7s 2 Exception to Building Up Principle Electronic Configuration of Transition Metal cations d-block and f-block elements d orbitals are lower in energy than s orbitals f orbitals are lower in energy than d orbitals E.g. Neutral atom Fe :[Ar] 3d 6 2 4s 3+ 5 Cation, Fe :[Ar] 3d Chemistry 481, Spring 2017, LA Tech Chapter-1-77

12. Give the ground state electronic configurations of following in core format. a) Mo b) Ag c) V 3+ d) Mn e) Cr 2+

2+ 3+ Co f) 6+ g) Cr h) Gd 3+ Chemistry 481, Spring 2017, LA Tech Chapter-1-78 Magnetic Properties of Atoms a) Paramagnetism?

attracted to magnetic field due to un-paired electrons. b) Ferromagnetism? attracted very strongly to magnetic field due to un-paired electrons. c) Diamagnetism? Repelled by a magnetic field due to paired electrons. Chemistry 481, Spring 2017, LA Tech Chapter-1-79 13. Give the ground state electronic configurations of the following in valence orbital box format and give the number of unpaired electrons. a) Mn: b) Co: c) Fe2+: d) Nd3+: Chemistry 481, Spring 2017, LA Tech

Chapter-1-80 Periodic trends Many trends in physical and chemical properties can be explained by electron configuration. Well look at some of the more important examples. Atomic radii Ionic radii First ionization energies Electron affinities Chemistry 481, Spring 2017, LA Tech Chapter-1-81 How does Ionic radii of elements vary? Cations have smaller radii than neutral atoms.

Anions have larger radii than neutral atoms The more charge on the ion more effect on the radii. Chemistry 481, Spring 2017, LA Tech Chapter-1-82 14. How do you measure atomic (ionic) radii (size)? Chemistry 481, Spring 2017, LA Tech Chapter-1-83 Types of Atomic Radii 1 Covalent Radii: Radii based on covalently liked atoms in covalently bonded molecules. 2 Van der Waals Radii: Radii based on non bonded atoms in solids. 3 Metallic Radii (12-coordinate):Radii based on metallic solids.

4 Ionic Radii: Radii based on bond distances in I Onic solids. Which one is the largest Radii? Chemistry 481, Spring 2017, LA Tech Chapter-1-84 Atomic radii of elements going down a group? Chemistry 481, Spring 2017, LA Tech Chapter-1-85 Lanthanoide Contration Filling of the 4f orbitals in the lanthanides, which occur within the third series of transition elements, causes these transition metals to be smaller than expected because the 4f orbitals are very poor nuclear shielders and Zeff of 6s2 obitals increase and the atomic radii decrease. 3rd-series elements have nearly the same effective nuclear charge as the 2nd-series elements, and thus, nearly the same size

Ce [Xe] Chemistry 481, Spring 2017, LA Tech 4f 1 1 2 5d 6s Chapter-1-86 15. Why the atomic radius of Zr (1.64) which is in 5th period is almost similar to a element, Hf (1.65) in 6th period. Chemistry 481, Spring 2017, LA Tech Chapter-1-87 Ionic radii Cations These are smaller than the atoms from which they are formed.

Anions These are larger than the atoms from which there are formed.. Chemistry 481, Spring 2017, LA Tech Chapter-1-88 Isoelectronic configurations Species that have the same electron configurations. Example Each of the following has an electron configuration of 1s2 2s2 2p6 O2- F- Ne Na+ Mg2+ Al3+ Chemistry 481, Spring 2017, LA Tech Chapter-1-89 Ionization energy First ionization energy

The energy to remove one electron from a neutral atom in the gas phase. A(g) + first ionization energy A+(g) + e This indicates how easy it is to form a cation. Metals tend to have lower first ionization energies than nonmetals. They prefer to become cations. Chemistry 481, Spring 2017, LA Tech Chapter-1-90 First ionization energy 2500 He Ne First ionization energy (kJ/mol) 2000 Ar

1500 Kr Xe Rn 1000 500 0 0 20 40 60 80 100 Atomic number

Chemistry 481, Spring 2017, LA Tech Chapter-1-91 Changes of I.E. Across a period Chemistry 481, Spring 2017, LA Tech Chapter-1-92 16. Why is the ionization energy of P (11.00 eV) greater than S (10.36 eV)? Chemistry 481, Spring 2017, LA Tech Chapter-1-93 How does Electron Affinity vary in the periodic table? Electron Affinity depends on Zeff of the nucleus to the outermost electron in the valence shell.

Going down the group Zeff for the outer most shell decrease hence the Electron Affinity also increase Going across the period Zeff for the outer most shell increase hence the Electron Affinity also decrease Chemistry 481, Spring 2017, LA Tech Chapter-1-94 Electron affinity Chemistry 481, Spring 2017, LA Tech Atomic number Chapter-1-95 Electronegativity The ability of an atom that is bonded to another atom or atoms to attract electrons to itself. It is related to ionization energy and electron affinity. It cannot be directly measured.

The values are unitless since they are relative to each other. The values vary slightly from compound to compound but still provide useful qualitative predictions. Chemistry 481, Spring 2017, LA Tech Chapter-1-96 Electronegativities 4 3.5 Electronegativity Electronegativityis isaa Electronegativity 3 periodic periodicproperty. property. 2.5 2

1.5 1 0.5 0 Chemistry 481, Spring 2017, LA Tech 20 40 Atomic number 60 80 100 Chapter-1-97 17. How you define electronegativity? Chemistry 481, Spring 2017, LA Tech Chapter-1-98

Electronegativity Scales Pauling Electronegativity, cP Mulliken Electronegativity, cM The Allred-Rochow, cAR Sanderson electronegativity Allen electronegativity Chemistry 481, Spring 2017, LA Tech Chapter-1-99 Pauling Electronegativity, cP EA-A and EB-B bond-energy of homonuclear A-A & B-B diatomic molecules EA-B bond-energy of heteronuclear A-B diatomic molecule cA cB are electronegativity values of A and B Pauling comments that it is more accurate to use the geometric mean rather than the arithmetic mean Chemistry 481, Spring 2017, LA Tech

Chapter-1-100 Mulliken Electronegativity, cM The Mulliken electronegativity can only be calculated for an element for which the electron affinity is known For ionization energies and electron affinities in electronvolts m For energies in kilojoules per mole m Chemistry 481, Spring 2017, LA Tech Chapter-1-101 The Allred-Rochow, cAR The effective nuclear charge, Zeff experienced by valence electrons can be estimated using Slater's rules, while the surface area of an atom in a molecule can be taken to be proportional to the square of the covalent radius, rcov. When rcov is

expressed in ngstrms, AR Chemistry 481, Spring 2017, LA Tech Chapter-1-102 Sanderson, cs Sanderson has also noted the relationship between electronegativity and atomic size, and has proposed a method of calculation based on the reciprocal of the atomic volume. Allen, cA The simplest definition of electronegativity is that of Allen, bases on average energy of the valence electrons in a free atom where s,p are the one-electron energies of s- s,p are the one-electron energies of sand p-electrons in the free atom and ns,p are the number of s- and p-electrons in the valence shell. Chemistry 481, Spring 2017, LA Tech Chapter-1-103

18. Calculate the electronegativity (X) (Xm, Xar) for Cl. [ Xm= 1/2(I+Ae); Xar= 0.744+ 0.359 Zeff/r2 ] a) Xm When Ei and Eea kJ per mol Xm= 1.97 x 10-3(1251 + 349 ) + 0.19 Xm = 3.342 (3.54) a) Xar When r ( 0.99 Angstroms) and Zeff = 6.12 Xar= 0.359 Zeff/r2 + 0.744 Xar = 2.98 (2.83) Chemistry 481, Spring 2017, LA Tech Chapter-1-104

Recently Viewed Presentations

  • Research Questions

    Research Questions

    Third Level 2. Third Level Every subordinate level must directly support the level above it. Heading Research Question Thesis Title I. First Level (body thesis) A. Second Level (general evidence - cited) 1. Third Level (further specific evidence and/or general...
  • Big ideas  The eyes have it 1. 2.

    Big ideas The eyes have it 1. 2.

    Big ideas "The eyes have it" "Context is everything" What is the nature of the relationship between ??2emissions and energy consumption per person ?
  • HETEROGENEOUS SYSTEM ARCHITECTURE (HSA) AND THE SOFTWARE ECOSYSTEM

    HETEROGENEOUS SYSTEM ARCHITECTURE (HSA) AND THE SOFTWARE ECOSYSTEM

    The coherent memory heap is the default heap on HSA and is always present. Implementations may also provide a non-coherent heap for advance programmers to request when they know there is no sharing between processor types. The software stack is...
  • Qualifications Update Charlie ODonnell CfE Liaison Manager Quality

    Qualifications Update Charlie ODonnell CfE Liaison Manager Quality

    Centres will be notified of selection in advance of each round via new NQ QA software on SQA Connect. Selections will specify: Unit (Nat1/2 or Nat3-5) or Course (IACC) Event/Postal or Visiting. Live entries will be monitored throughout the year
  • VA Center for Faith-based and Neighborhood Partnerships (CFBNP)

    VA Center for Faith-based and Neighborhood Partnerships (CFBNP)

    "We are going to take (the) 131,000 homeless Veterans off the streets over the next five years … To do this well, we will have to attack the entire downward spiral that ends in homelessness - we must offer education,...
  • High Performance Buildings - EMEIA

    High Performance Buildings - EMEIA

    Awareness can be partnered through Southface (Candice Moore Groves, Commercial Green Building Services Project Manager, 404-604-3592, [email protected]) See the "EERE - Creating An Energy Awareness Program" Sub-Directory. Subscribe Customer to Energy Awareness & Behavior Modification Newsletter
  • What are the key population issues in Africa

    What are the key population issues in Africa

    Woodrow Wilson Center. 5 June 2012. Violet I Murunga, Nyokabi R Musila, Rose N Oronje and Eliya M Zulu ... Gill Walt and Lucy Gilson proposed a 'Policy Analysis Triangle' in 1994 to help policy analysts think more systematically about...
  • Combinatorial Optimization in Computational Biology

    Combinatorial Optimization in Computational Biology

    This approach was introduced by Pavel Pavzner. A proposed approach to sequencing DNA Graph Traversals, Genes and Matroids: An Efficient Special Case of the Traveling Salesman Problem D. Gusfield, R. Karp, L. Wang, P. Stelling Discrete Applied Math 88 special...