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WLU CH110 Summaries.pdf - lOMoARcPSD|10729405 Terra...

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Terra ChisholmINTRODUCTONIons-Anionis a charged chemical species (monatomic or polyatomic)-Monatomic ions:-A ion is charged because the number of electrons do not equal the number of protons-Ananionis an ion with a negatve charge(e.g. Cl,O2−,H,S2−, N3−)Cl + e-Cl-O + 2e-O2--Acatonis an ion with positve charge (e.g. H+,Na+,Fe2+,He+)HH++ e-FeFe2++ 2e--Polyatomic ions-Ex. H3O+,Cr2O72−, NO3−,CO32−, MnO4)-These are groups of atoms in which the total number of electrons do not equal the number of protons
Terra Chisholm5.1 ORBITAL ENERGIES-Review of orbital energies for the hydrogen atom (Z= 1, 1eatom)-The energy of an orbital with principal quantum number is given by-The energy of the orbital increases asnincreases (less stable)-The most stable level isn= 1(ground state)-Less stable statesn> 1(excited states)What about multelectron atoms?-Basic idea is the same-But energies cannot be calculated using the above equaton-Variatons in nuclear charge (Z) and number of electrons infuence electrical forces between nucleus andelectrons-Changes in electrical forces cause changes in orbital energiesEfect of Nuclear Charge:-Increasing nuclear charge (Z) lowers the energy of orbitals-Orbital energies are much lower for He+-The larger nuclear charge of He+means larger forces ofatracton-The He+orbitals are more stableEfects of Other Electrons:-Electron-electron repulsion:-Each negatvely charged electron is atracted to the positvely charged nucleus (unlike charges atract)-Each electron is repelled by all other electrons in the atom (like charges repel)-Electron-electron repulsion accounts for the lower energy required to remove an electron from Hecompared to He+En=−2.10×1018Jn2
Terra Chisholm-All multelectron atoms have electron-electron repulsionScreening:-Screeningis when electron-electron repulsion cancels or reduces the amount of atracton between anelectron and the nucleusThe nuclear charge that electron-B experiences is lessthat the full +2 nuclear charge that electron-Aexperiences-Efectve Nuclear Charge(Zef)is the nuclear charge an electron experiences as a result of screeningZef=Z− efects of screeningZef(eA) = +2Zef(eB) < +2-Screening and size of orbitals:-Electrons in compact orbitals screen beter than electron in larger difuse orbitals-Screening decreases as orbital size increases-As the principle quantum number (n)increases the screening ability of electrons in those orbitalsdecreases-The 1sorbital screens the 2sand 3sorbitals-The 2sorbital screens the 3sorbital-The 3sorbital screens larger orbitals (e.g.n= 4, 5, 6 etc.)-Electrons in lower azimuthal quantum numbers (l) screen electrons in higher azimuthal quantumnumbers-Electrons insorbitals screen electrons inp,dandforbitals-Electrons inporbitals screen electrons indandforbitals-Electrons indorbitals screen electrons inforbitalsThis part of the3porbital screens the3dorbital

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Term
Winter
Professor
N/A
Tags
Atom, Electron, Periodic Table, Chemical bond, Michael Ayad

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