#KA AP Chem

[studentbyday]

Molecular and ionic compound structure and properties Pt. 1

Types of chemical bonds - really a spectrum of bonds

All these occur b/c atoms are constantly moving and colliding unless at absolute 0. Goal of intramolecular bonds is to obtain full valence octets or full valence shells.

Ionic bonds - transfer of electron(s) from 1 atom to another b/c of very big difference in electronegativity b/t the atoms involved (1 has high electronegativity, other has low electronegativity), anion + cation = attracted to each other → electrically neutral compound, usually occurs between metal (b/c it typically forms cations) and nonmetal (b/c it typically forms anions)

Covalent bonds - sharing of electron(s) b/t atoms, sometimes equal sharing (non-polar), other times unequal sharing (polar), usually occurs between nonmetals that aren’t noble gases aka that don’t have full valence shells or full valence octets (same nonmetal element or not)

If bond is b/t same element, it’s non-polar b/c they have the same electronegativity

If bond is b/t different elements b/t w/ same electronegativity, it’s non-polar

If 1 element has a higher electronegativity than the other, but not enough of an electronegativity difference to cause a transfer of electron(s), it forms a polar bond

Covalent bonds tend to occur b/t elements w/ a range of relatively high electronegativities, i.e. nonmetals

Metallic bonds - metal atoms’ valence electrons are loosely held b/c they all have low electronegativity, not fixed to a single atom, so when metal atoms are put together, you can imagine each atom donating electron(s) to form a “sea of electrons and metal cations”. This electrostatic attraction b/t metal cations and the sea of electrons gives metals their unique properties like electrical conductivity (b/c electrons are free to move), malleability (can bend it easily) and ductility (can roll into wires easily).

Stated another way, metallic bonds occur b/t atoms w/ similar, low electronegativities, i.e. metals.

Metalloids have properties b/t metals and nonmetals, e.g. semiconductivity

Intramolecular force and potential energy

Bond length aka internuclear distance = the distance b/t the centers/nuclei of the atoms in a diatomic molecule

For bonded atoms, you have the equilibrium bond length, which is stable - the bond length at which you have the minimum potential energy (this is a negative number, e.g. -432 kJ/mol for diatomic hydrogen)

Expected internuclear distance for diatomic molecules at standard temperature and pressure

If you pull the atoms apart, you increase the bond length and therefore the potential energy from this low point, and if you keep pulling them apart, potential energy increases until it approaches 0 potential energy - the potential energy at which the atoms are no longer bonded together or associated w/ each other. This occurs because the Coulomb forces b/t them gets weaker and weaker the further you pull them apart.

Bond energy is the amount of energy you need to put in to break the bond b/t the atoms (e.g. 432 kJ/mol for diatomic hydrogen)

The higher the order of the bond (i.e. increasing from single to double to triple bonds), the larger its bond energy

If you push the atoms closer together, you decrease the bond length, which increases the potential energy from this low point - higher than 0 potential energy if you keep pushing them together. This increase in potential energy is due to increased repulsion b/t the electrons (negative charges) and the positive charges (protons in nucleus).

Identifying diatomic molecules’ potential energy curves: Min. potential energy is a function of how small the atomic radii are and order of the bond

The smaller the radii, the closer the nuclei will be, so smaller equilibrium bond length

E.g. looking at periodic table, H has the smallest atomic radius, so it makes sense that H2′s internuclear distance is the smallest; but O has slightly smaller atomic radius than N, so based on bond length alone, you’d think that the salmon-colored curve is O2′s and the purple is N2′s b/c the salmon-colored curve has a slightly smaller internuclear distance. But in general, conclusions from bond order (differences in bond energy) trump conclusions from atomic radii (differences in bond length/internuclear distance). In this case, for e.g., N2′s triple bond pushes the N atoms closer together even if they might be a little bit bigger in radius than the O atoms.

The higher the order of the bond, the closer together the atoms will be, so smaller equilibrium bond length, and the higher the bond energy will be, so the more negative the min. potential energy

E.g. based on bond order, H2 has a single covalent bond, so it’s got the lowest bond energy; O2 has a double covalent bond, so it’s got a bond energy greater than H2 but less than N2 which has a triple covalent bond; N2 therefore has the highest bond energy

Lattice energy (kJ/mol) = energy needed to separate ions in a crystal lattice (ionic compound structure) into individual gaseous ions (same concept as bond energy for covalent bonds)

Lattice = 3D structure of atoms/ions w/ repeating pattern

E.g. NaCl crystal lattice: (Na+ is smaller than Cl-, even if Na is on left of periodic table and the trend is to decrease atomic radius as you move right, b/c Na loses an electron, so it loses a shell to obtain the electron configuration of Ne but w/ 1 more proton, so it has a really strong pull on its electrons, leading to a small ionic radius; meanwhile, Cl gains an electron and obtains the electron configuration of Ar but with 1 less proton, so it doesn’t have as strong a pull on its electrons compared to Na+, so it has a larger ionic radius)

Depends on strength of interactions b/t cations and anions in the lattice, w/c can be estimated using Coulomb’s law: magnitude of the force  Fₑ = (q₁q₂)/r²

If the q’s charges are opposite, F is attractive; if the q’s charges are like, F is repulsive

Stronger interactions (stronger electrostatic force) occur b/t ions w/ larger charges and ions that have a smaller distance between each other

The stronger the interactions, the greater the lattice energy

Structure of ionic solids

Structure of metals and alloys

Alloys = mixtures of metal elements that maintain many of metals’ properties while creating other useful properties (e.g. stainless steel is much more resistant to corrosion than basic steel, basic steel is stronger than iron by itself)

Interstitial alloys - 1 atom has significantly larger radius than the other, e.g. steel = iron mixed w/ carbon w/c = much smaller than Fe and able to fit in gaps b/t iron atoms

Substitutional alloys - atoms involved have similar radius, e.g. brass = Cu + Zn w/c have similar atomic radii

Combo of both - e.g. stainless steel: Fe, C w/c is smaller than Fe, and Cr w/c is similar in radius to Fe

[444namesplus]

aba abe abh abi abo abu acha ache achi acho achu ada ade adh adi ado adu afa afe afh afi afo afu aga age agh agi ago agu aha ahe ahi aho ahu aja aje aji ajo aju aka ake akh aki ako aku al ala ale alh ali alo alu am ama ame ami amo amu an ana ane ani ano anu apa ape aph api apo apu ar ara are arh ari aro aru asa ase ash asi aso asu ata ate ath ati ato atu ava ave avi avo avu az aza aze azh azi azo azu ba bal bam ban bar baz be bel bem ben ber bez bha bhe bhi bho bhu bi bil bim bin bir biz bo bol bom bon bor boz bu bul bum bun bur buz cha chal cham chan char chaz che chel chem chen cher chez chi chil chim chin chir chiz cho chol chom chon chor choz chu chul chum chun chur chuz da dal dam dan dar daz de del dem den der dez dha dhe dhi dho dhu di dil dim din dir diz do dol dom don dor doz du dul dum dun dur duz eba ebe ebh ebi ebo ebu echa eche echi echo echu eda ede edh edi edo edu efa efe efh efi efo efu ega ege egh egi ego egu eha ehe ehi eho ehu eja eje eji ejo eju eka eke ekh eki eko eku el ela ele elh eli elo elu em ema eme emi emo emu en ena ene eni eno enu epa epe eph epi epo epu er era ere erh eri ero eru esa ese esh esi eso esu eta ete eth eti eto etu eva eve evi evo evu ez eza eze ezh ezi ezo ezu fa fal fam fan far faz fe fel fem fen fer fez fha fhe fhi fho fhu fi fil fim fin fir fiz fo fol fom fon for foz fu ful fum fun fur fuz ga gal gam gan gar gaz ge gel gem gen ger gez gha ghe ghi gho ghu gi gil gim gin gir giz go gol gom gon gor goz gu gul gum gun gur guz ha hal ham han har haz he hel hem hen her hez hi hil him hin hir hiz ho hol hom hon hor hoz hu hul hum hun hur huz

iba ibe ibh ibi ibo ibu icha iche ichi icho ichu ida ide idh idi ido idu ifa ife ifh ifi ifo ifu iga ige igh igi igo igu iha ihe ihi iho ihu ija ije iji ijo iju ika ike ikh iki iko iku il ila ile ilh ili ilo ilu im ima ime imi imo imu in ina ine ini ino inu ipa ipe iph ipi ipo ipu ir ira ire irh iri iro iru isa ise ish isi iso isu ita ite ith iti ito itu iva ive ivi ivo ivu iz iza ize izh izi izo izu ja jal jam jan jar jaz je jel jem jen jer jez ji jil jim jin jir jiz jo jol jom jon jor joz ju jul jum jun jur juz ka kal kam kan kar kaz ke kel kem ken ker kez kha khe khi kho khu ki kil kim kin kir kiz ko kol kom kon kor koz ku kul kum kun kur kuz la lal lam lan lar laz le lel lem len ler lez lha lhe lhi lho lhu li lil lim lin lir liz lo lol lom lon lor loz lu lul lum lun lur luz ma mal mam man mar maz me mel mem men mer mez mi mil mim min mir miz mo mol mom mon mor moz mu mul mum mun mur muz na nal nam nan nar naz ne nel nem nen ner nez ni nil nim nin nir niz no nol nom non nor noz nu nul num nun nur nuz oba obe obh obi obo obu ocha oche ochi ocho ochu oda ode odh odi odo odu ofa ofe ofh ofi ofo ofu oga oge ogh ogi ogo ogu oha ohe ohi oho ohu oja oje oji ojo oju oka oke okh oki oko oku ol ola ole olh oli olo olu om oma ome omi omo omu on ona one oni ono onu opa ope oph opi opo opu or ora ore orh ori oro oru osa ose osh osi oso osu ota ote oth oti oto otu ova ove ovi ovo ovu oz oza oze ozh ozi ozo ozu pa pal pam pan par paz pe pel pem pen per pez pha phe phi pho phu pi pil pim pin pir piz po pol pom pon por poz pu pul pum pun pur puz ra ral ram ran rar raz re rel rem ren rer rez rha rhe rhi rho rhu ri ril rim rin rir riz ro rol rom ron ror roz ru rul rum run rur ruz sa sal sam san sar saz se sel sem sen ser sez sha she shi sho shu si sil sim sin sir siz so sol som son sor soz su sul sum sun sur suz ta tal tam tan tar taz te tel tem ten ter tez tha the thi tho thu ti til tim tin tir tiz to tol tom ton tor toz tu tul tum tun tur tuz uba ube ubh ubi ubo ubu ucha uche uchi ucho uchu uda ude udh udi udo udu ufa ufe ufh ufi ufo ufu uga uge ugh ugi ugo ugu uha uhe uhi uho uhu uja uje uji ujo uju uka uke ukh uki uko uku ul ula ule ulh uli ulo ulu um uma ume umi umo umu un una une uni uno unu upa upe uph upi upo upu ur ura ure urh uri uro uru usa use ush usi uso usu uta ute uth uti uto utu uva uve uvi uvo uvu uz uza uze uzh uzi uzo uzu va val vam van var vaz ve vel vem ven ver vez vi vil vim vin vir viz vo vol vom von vor voz vu vul vum vun vur vuz za zal zam zan zar zaz ze zel zem zen zer zez zha zhe zhi zho zhu zi zil zim zin zir ziz zo zol zom zon zor zoz zu zul zum zun zur zuz

[studentbyday]

photoelectron spectroscopy (PES)

PES uses the photoelectron effect which is basically describing how, when you zap a sample with photons of electromagnetic radiation (energy), you remove/eject its electrons. This uses the concept of ionization energy. Radiation = ionization energy + some extra. You're giving the sample enough energy to remove its electrons (ionization energy) and the extra energy gives the electron enough energy to move (kinetic energy). The electron's ionization energy is also called binding energy (because...???).

This is another way to say it: energy of photon = binding energy + kinetic energy of electron. Or abbreviated, Ephoton = BE + KEelectron

If you want to break it down further, energy of photon = Planck's constant*frequency of photon in Hertz = BE + KEelectron, or abbreviated: hv = BE + KEelectron

Solving for BE, that's BE = hv - KEelectron

PES creates a graph showing the number of electrons ejected on the y-axis vs their binding energy in electron volts eVeVstart text, e, V, end text) or megajoules (MJMJstart text, M, J, end text) per mole.onn the x-axis. How does it create this graph?

High-energy photons, usually UV or X rays, hit a sample of free atoms or molecules (the photoelectric effect was originally described for metal surfaces but it also applies to free atoms or molecules), ejecting their electrons. These electrons' kinetic energies are measured with an energy analyser. A detector then counts how many electrons of a certain kinetic energy there are. From there, we can calculate the binding energies for the electrons ejected (called photoelectrons) using the equation above. Since the energy in the photons is constant for all electrons ejected, the greater the electron's kinetic energy, the less their binding energy, and vice versa.

[444namesplus]

a aa aach aaf aah aak aam aan aap aar aas aash aat aath ach ae aech aef aeh aek aem aen aep aer aes aesh aet aeth af ah аi aich aif aih aik aim ain aip air ais aish ait aith ak am an ao aoch aof aoh aok aom aon aop aor aos aosh aot aoth ap ar as ash at ath au auch auf auh auk aum aun aup aur aus aush aut auth cha chach chaf chah chak cham chan chap char chas chash chat chath che chech chef cheh chek chem chen chep cher ches chesh chet cheth chi chich chif chih chik chim chin chip chir chis chish chit chith cho choch chof choh chok chom chon chop chor chos chosh chot choth chu chuch chuf chuh chuk chum chun chup chur chus chush chut chuth e ea each eaf eah eak eam ean eap ear eas eash eat eath ech ee eech eef eeh eek eem een eep eer ees eesh eet eeth ef eh ei eich eif eih eik eim ein eip eir eis eish eit eith ek em en eo eoch eof eoh eok eom eon eop eor eos eosh eot eoth ep er es esh et eth eu euch euf euh euk eum eun eup eur eus eush eut euth fa fach faf fah fak fam fan fap far fas fash fat fath fe fech fef feh fek fem fen fep fer fes fesh fet feth fi fich fif fih fik fim fin fip fir fis fish fit fith fo foch fof foh fok fom fon fop for fos fosh fot foth fu fuch fuf fuh fuk fum fun fup fur fus fush fut futh ha hach haf hah hak ham han hap har has hash hat hath he hech hef heh hek hem hen hep her hes hesh het heth hi hich hif hih hik him hin hip hir his hish hit hith ho hoch hof hoh hok hom hon hop hor hos hosh hot hoth hu huch huf huh huk hum hun hup hur hus hush hut huth i ia iach iaf iah iak iam ian iap iar ias iash iat iath ich ie iech ief ieh iek iem ien iep ier ies iesh iet ieth if ih ii iich iif iih iik iim iin iip iir iis iish iit iith ik im in io ioch iof ioh iok iom ion iop ior ios iosh iot ioth ip ir is ish it ith iu iuch iuf iuh iuk ium iun iup iur ius iush iut iuth

ka kach kaf kah kak kam kan kap kar kas kash kat kath ke kech kef keh kek kem ken kep ker kes kesh ket keth ki kich kif kih kik kim kin kip kir kis kish kit kith ko koch kof koh kok kom kon kop kor kos kosh kot koth ku kuch kuf kuh kuk kum kun kup kur kus kush kut kuth ma mach maf mah mak mam man map mar mas mash mat math me mech mef meh mek mem men mep mer mes mesh met meth mi mich mif mih mik mim min mip mir mis mish mit mith mo moch mof moh mok mom mon mop mor mos mosh mot moth mu much muf muh muk mum mun mup mur mus mush mut muth na nach naf nah nak nam nan nap nar nas nash nat nath ne nech nef neh nek nem nen nep ner nes nesh net neth ni nich nif nih nik nim nin nip nir nis nish nit nith no noch nof noh nok nom non nop nor nos nosh not noth nu nuch nuf nuh nuk num nun nup nur nus nush nut nuth o oa oach oaf oah oak oam oan oap oar oas oash oat oath och oe oech oef oeh oek oem oen oep oer oes oesh oet oeth of oh oi oich oif oih oik oim oin oip oir ois oish oit oith ok om on oo ooch oof ooh ook oom oon oop oor oos oosh oot ooth op or os osh ot oth ou ouch ouf ouh ouk oum oun oup our ous oush out outh pa pach paf pah pak pam pan pap par pas pash pat path pe pech pef peh pek pem pen pep per pes pesh pet peth pi pich pif pih pik pim pin pip pir pis pish pit pith po poch pof poh pok pom pon pop por pos posh pot poth pu puch puf puh puk pum pun pup pur pus push put puth ra rach raf rah rak ram ran rap rar ras rash rat rath re rech ref reh rek rem ren rep rer res resh ret reth ri rich rif rih rik rim rin rip rir ris rish rit rith ro roch rof roh rok rom ron rop ror ros rosh rot roth ru ruch ruf ruh ruk rum run rup rur rus rush rut ruth sa sach saf sah sak sam san sap sar sas sash sat sath se sech sef seh sek sem sen sep ser ses sesh set seth sha shach shaf shah shak sham shan shap shar shas shash shat shath she shech shef sheh shek shem shen shep sher shes shesh shet sheth shi shich shif shih shik shim shin ship shir shis shish shit shith sho shoch shof shoh shok shom shon shop shor shos shosh shot shoth shu shuch shuf shuh shuk shum shun shup shur shus shush shut shuth si sich sif sih sik sim sin sip sir sis sish sit sith so soch sof soh sok som son sop sor sos sosh sot soth su such suf suh suk sum sun sup sur sus sush sut suth ta tach taf tah tak tam tan tap tar tas tash tat tath te tech tef teh tek tem ten tep ter tes tesh tet teth tha thach thaf thah thak tham than thap thar thas thash that thath the thech thef theh thek them then thep ther thes thesh thet theth thi thich thif thih thik thim thin thip thir this thish thit thith tho thoch thof thoh thok thom thon thop thor thos thosh thot thoth thu thuch thuf thuh thuk thum thun thup thur thus thush thut thuth ti tich tif tih tik tim tin tip tir tis tish tit tith to toch tof toh tok tom ton top tor tos tosh tot toth tu tuch tuf tuh tuk tum tun tup tur tus tush tut tuth u ua uach uaf uah uak uam uan uap uar uas uash uat uath uch ue uech uef ueh uek uem uen uep uer ues uesh uet ueth uf uh ui uich uif uih uik uim uin uip uir uis uish uit uith uk um un uo uoch uof uoh uok uom uon uop uor uos uosh uot uoth up ur us ush ut uth uu uuch uuf uuh uuk uum uun uup uur uus uush uut uuth

[studentbyday]

day 12/14 of chem & day 4/24 of reading

Wrote some more quantum behavior notes

Finished resonance and formal charge (KA AP Chem U2)

[studentbyday]

I'm really happy with the Rilakkuma in the library aesthetic...but... If Rilakkuma is me, Rilakkuma is turning into the library version of lofi girl... Just stuck in the library... (Though mine is not a physical library, just KA's chemistry library XD). Ohhh there is sm info to cover. I was and still kinda am nervous for university chemistry, which is why I'm attempting to cover ALL of KA's chemistry library and AP Chem course in 14 days because that's about how much time I have between Winter term final season and summer classes... But...Idk if that's possible. Not panicking. Just...concerned.