Download Chemistry 103 Exam 3: Electron Configurations and Bonding Theories and more Exams Chemistry in PDF only on Docsity!
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Which orbital is the electron in? - Correct answer l (L) value which orientation is the electron in? - Correct answer m sub L value n value - Correct answer use periodic table (period #) L value - Correct answer what orbital its in (s, p, d, f) m sub L value - Correct answer what orientation of the orbital is it in?---every electron in the atom has unique values for n, l, ml Electron configurations show... - Correct answerthe orbitals which orbitals are in an atom and how the electrons fill
Electron configurations focus on... - Correct answer ground state configuration (lowest energy state)-no electrons are jumping to new energy levels ie... Hydrogen-1 electron...n=1, l=0, ml= how many possible electrons can fit into the s orbital? - Correct answerorbital two electrons go into the s
how many possible electrons can fit into the p orbital? - Correct answer six electrons go into the p orbital how many possible electrons can fit into the d orbital? - Correct answerorbital ten electrons go into the d
how many possible electrons can fit into the f orbital? - Correct answer fourteen electrons go into the f orbital period number - Correct answerfor S and P block the number on the left of the periodic table=n (principle energy level)--
for d block...(n-1) for f block... (n-2) Aufbau Principle - Correct answer defines pattern of orbital filling: fill from lowest to highest energy levels...(n-1)d comes after (n)s because energy levels get closer as n increases. configurations of transition metals - Correct answer ns filled before (n-1)d orbitals... ie. Fe: 1s2 2s2 2p6 3s2 3p6 4s2 3d exceptions: extra stability when half filled or fully filled d orbital (only for transition metals and only atomicconfiguration-not ions)
Cr column and Cu column... ie... Cr expected: 1s2 2s2 2p6 3s2 3p6 4s2 3d Cr actual: 1s2 2s2 2p6 3s2 3p6 4s1 3d Cu expected: 1s2 2s2 2p6 3s2 3p6 4s2 3d
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Cu actual: 1s2 2s2 2p6 3s2 3p6 4s1 3d Electron configurations of ions - Correct answerthe same number of electrons as the nearest noble gas (stable) metals and non metals: lose and gain electrons to have
main group: remove electrons in reverse order of filling ie... Ca: (Ar)4s2---Ca2+: (Ar)4s0=(Ar) transition metals: remove electrons from the highest "n" value first ie... Co: (Ar)4s2 3d7---Co3+:(Ar)4s 3d ie...Fe: (Ar) 4s2 3d6---Fe2+: (Ar) 4s0 3d 6 Valence electrons - Correct answerproperties of an atom electrons that are important in chem. bonding... helps determine the
-total number of valence electrons is show n at the top of each column in the per. table How to determine which electrons are valence - Correct answer main group: electrons in outermost (highest value of n) energy level are valence: ie... Si: 1s2 2s2 2p6 3s2 3p -3s2 and 3p2 are valence transition metals/elements+ lanth and act: electrons in outermost energy level+outermost d or f electrons ie...Co 1s2 2s2 2p6 3s2 3p6 4s2 3d7Valence: 4s2 and 3d
Core electrons - Correct answer non valence-non reactive electrons in complete or filled energy levels ie... Si: (1s2 2s2 2p6) 3s2 3p core electrons are in brackets and valence are not in brackets M sub S - Correct answer electron spin quantum number: +1/2: arrow is up, -1/2: arrow is down orbital diagrams - Correct answer show a pictoral view of how electrons fill up orbitals based on configuration
valence orbital diagrams: use condensed configurations and noble gas symbols to show which boxes are filled. Pauli Exclusion Principle - Correct answerquantum numbers (n,l,ml,ms) no two electrons in an atom can have the same four
-each orbital can have a maximum of only two electrons with opposite spins. -the number of electrons in a sublevel is twice the number of orbitals
ie.. S: 21 orbital: 2 electronsP: 23 electrons: 6 electrons d: 2*5 orbitals: 10 electrons
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Magnetic properties - Correct answer dependent on how electrons are filled or removed from orbitals -unpaired electrons: generate a magnetic field due to spin (+/- 1/2)-atom/ion with unpaired electrons is attracted to an external magnetic field (paramagnetic) -determined from electron configuration ie.. Silver has one unpaired electron, so it is paramagnetic -Atom or ion with all paired electrons is not attracted to an external magnetic field--DIAMAGNETIC ie.. Zn and Zn 2+ Ionization energy - Correct answer -positive value -energy needed to remove an electron from an atom (make it an ion--add energy to happen) -valence electrons are easier to remove than core electrons -first ionization energy (remove first electron) ie...Na (g)--Na+ + e-ALWAYS MAKING ELECTRONS AND ALWAYS IN GAS STATE
-larger Zeff on electron--more energy to remove (increased attraction to nucleus) -further away the electron is from nucleus, less energy it takes to remove -IE decreases down columns and increases across period to the right. IE increases up and to the right of the periodic table Successive ionization energy - Correct answer Takes more energy to remove successive electrons because the size is decreased each time-more protons than electrons, so electrons are held more tightly -electrons beyond noble gas config. are very tough to remove ie.. Na 1 IE: Na--Na+ and e-2 IE: Na+--Na2+ + e- 3 IE: Na2+--Na3= and e- Electron affinity (opposite of ionization energy)--likes electrons (EA) - Correct answerassociated with a neutral atom gaining an electron in gas state energy change
-ie. Fl Fl (gas) + electron--F- (gas) -accompanied by energy release--delta E is negative due to the attraction between the nucleus and incoming electron -generally increases across a period
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-most negative on the right side--halogens have the highest electron affinity since they would achievenoble has configuration
-lowest EA are the alkaline earth and noble gases (ask Dr. T why) Metallic character - Correct answer more reactive for losing electrons (how reactive are metals) -metals tend to lose electrons in reactions -moving right, metallic character (reactivity decreases) as you move toward the nonmetals -move down a column, non-MC increases--ionization energy increases, so does metallic character (all the trends on page 139) Bonding and Lewis Theory - Correct answer Bonding theories explain how atoms bond to form culs -predict combos of atoms are stable -predict shape of cul--chem and phys. properties Lewis Model: all about valence electrons (represented by dots) -uses valence to explain why bonds form -predicts properties: shape, size, polarity, etc. Why do chemical bonds form? - Correct answer to lower the potential energy between charged particles that compose atoms -charges with the same sign: potential energy is positive -charges with opposite signs: potential energy is negative-more negative the potential energy, more stable the bond is
-chemical bonds form when the potential energy of bonding atoms is less than the potential energy of separate atoms Ionic bonds - Correct answermetals have low ionization energy and the nonmetals have high electron affinity (like to gain electrons) electrons are transferred from the metal to the non metal because the
covalent bonds - Correct answer electrons are shared between two non metals -non metals have high ionization energy (no electrons are transferred) -potential energy favors sharing electrons Lewis Symbols - Correct answer element symbol represents nucleus and inner core electrons -dots represent the valence electrons and surround the element symbol Rules: pair up first two dots (s orbital) -put one electron on each side (p orbit)-make sure to have enough valence electrons
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Lewis theory predicts... - Correct answer formulas of culs and predicts which combos are stable
-accounts for.. covalent bonds (highly directional, elect are shared) -ionic bonds have arrays of atoms held together (non directional)
electrons are equally held between atoms-more stable-directional -covalent bonding between the same two atoms--equal/perfect bonding of electrons -covalent bonding between unlike atoms: unequal sharing of electrons because one atom pulls the electrons closer to itself: larger electron density on one atom (bond polarity)Polar: electron more on one side than another because of electronegativity
Polarity and electronegativity - Correct answer polar covalent bonds happen when two atoms with different electronegativity bond.. -atom with higher elctronegativity (more electron density) is going to be slightly negative -atom that has lower electronegativity is more positive Electronegativity - Correct answer the ability of an atom to attract electrons in a chemical bond -increases across a period to the right -decreases across a family Fluorine is most electronegative, Cs is least -larger differences in electronegativity--more polar the bond is ( lowercase delta negative on moreelectronegative atom)
Mnemonic for electronegativity: F O N Cl Br I S C H Bond dipole moment - Correct answer quantitative description of bond polarity (unit is Mew): a measure of bond polarity -higher the dipole moment, more polar the bond Mew=qr q=particle charger=distance between charges
*largest electronegativity difference=most polar Common Lewis structure patterns - Correct answer H: one bond, zero lone pairs B: 3 bonds, 0 lone pairs others: use formal charges
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Formal charge - Correct answer predict stability of lewis structure -calculating charge and ignoring electronegativity effects Formal charge=number of valence electrons - (number of non bonding electrons + 1/2 number of bondingelectrons)
Rules for best structure -sum of formal charges in neutral cul is zero -sum of formal charges in ion must equal ion charge -get the smallest possible values (0) is best -if zero isn't possible, put negative charge on the most electronegative atom Writing lewis structures - Correct answer-H is always terminal (at end) and forms only 1 bond 1) write skeletal structure
-more electronegative atoms in terminal positions -least electronegative atom is the central atom
- calculate number of valence electrons for each atom in the formula and add charges if necessary
- add your bonds and dots to get the total valence electrons you counted
- complete octets or duets and count
- if complete octets, extra electrons go on the central atom...elements in n=3 or lower can have expanded octets
- if central atom has no octet, bring in outer electrons to share
- assign formal charges to verify structure Resonance structures - Correct answerdiffers in positions of electrons, need resonance when more than one lewis structure exists for a molecule that
Resonance hybrid: actual structure is somewhere in between Bond order: number of bonds/number of locations: intermediate between single and double bonds -must have identical connectivity-only move positions of electrons -Resonance stabilization: electrons are spread out (delocalized) and energy is lowered, structure is morestable
ie.. NO3- Three different permutations of a double bond Exceptions to octet rule - Correct answer Odd electron species: one unpaired electron (free radical)
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3 electron groups - Correct answer option 1: 3 bonding groups, zero lone pairs -electron geo: trigonal planar-molecular geo: trigonal planar angle: 120 degrees ie.. BF option 2: 2 bonding groups, 1 lone pair-electron geo: trigonal planar molecular geo: bentangle: less than 120 degrees
ie... SO 4 electron groups - Correct answer option 1: 4 bonding groups, zero lone pairs -electron geo: tetrahedral-molecular geo: tetrahedral angle: 109.5 degrees-need to use wedge and dash for 3D notation
ie.. CF option 2: 3 bonding groups, one lone pair -electron geo: tetrahedralmolecular geo: trigonal planar angle: less than 109.5 (107)ie.. NH
Option 3: 2 bonding groups, 2 lone pairs -electron geo: tetrahedral-molecular geo: bent idealized angle: less than 109.5 (104.5) 5 electron groups around central atom - Correct answer option 1: 5 bonding pairs, 0 lone pairs EG: trigonal bipyramidalMG: trigonal bipyramidal -positions above and below central atom are axial positions-positions in same base plane as central atoms are equatorial positions (120 degrees apart)
-bond angle between axial and equatorial=90 degrees option 2: 4 bonding pairs, 0 lone pairs EG: trigonal bipyramidalMG: see-saw -no lone pairs in axial position OPTION 3: 3 bonding groups, one lone pairEG: trigonal bipyramidal MG: T-shaped OPTION 4: 2 bonding groups, 3 lone pairsEG: trigonal planar MG: linear
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*5 groups: always put lone pairs in equatorial position for 5 groups 6 Electron groups - Correct answer OPTION 1: 6 bonding groups, 0 lone pairs EG: octahedralMG: octahedral angle: 90 degrees-all positions equally spaced around central atom
OPTION 2: 5 BONDING GROUPS, 1 LONE PAIR EG: octahedralMG: square pyramidal angle: less than 90 degrees OPTION 3: 4 BONDING GROUPS, 2 lone pairsEG: octahedral MG: square planar-angle: 90 degrees
Molecule polarity (net dipole) - Correct answer need to consider molecule geo and whether the molecule has polar bonds -bond polarity: 2 ways...1. theory (electronegativity values)
- experiment: measuring dipole moment (M does not equal zero it's polar) if M=0, nonpolar Unsymmetrical molecular geometry - Correct answerdirection of arrows differences in EN--vector addition: see overall
non-bonding pairs affect molecule polarity b/c... - Correct answer they can cause distortions from the identical geometry -arrows cancel b/c they're equal, but opposite dipoles -no net dipole: non polar -draw arrow toward more electronegative atom Valence bond theory - Correct answer orbitals overlap to form bonds -orbitals in same direction w/ similar shape can overlap and bonds form What is the name of Dr. Turov's three year old daughter? - Correct answer Elise What language does Dr. Turov speak in addition to english? - Correct answer Russian Where was Dr. Turov born? - Correct answer Ukraine When are Dr. Turov's office hours and where? - Correct answer MLC Wednesday 10- Where did Dr. Turov go to graduate school? - Correct answer UW Madison
