CHEM UNIT 4

formal charges are used to formal charges are not ____, they're merely a means of Formal charge = formal charge also = formal charges MUST EX CO2 (controlling vs brought in) how choose best resonance? EX CYANATE ION - NCO-

select best resonance structure (if they r unequal) real charges! electron accounting that allows us to select the most favorable structures for molecules and ions valence e- # - (# lone e + 1/2 # shared e-) #e- wanted - #e- controlled Add to actual charge on particle!!(0 for neutral, charge value for ion) structures that minimize overal formal charge, smaller formal charges are preferred to large ones, like charges on adjacent atoms are not favorable, more neg formal charge should go on more EN atom ——resonance will look more like favorable structure

In Covalent bonding, atoms In covalent bonding, valence shells are covalent bonds are between electrostatic interactions in covalent bonds

share electrons cooperating- overlapping and share electrons two nonmetals- if share have low electroneg differences, if don't share equally then have higher electroneg differences attractions between electrons and nuclei, répulsions btwn electrons, répulsions btwn nuclei

a cation is always an anion is always ex Li+ vs Li cation always has a ____ cation vs atom (3 things)

smaller than their respective atoms larger than their respective atoms li+ has entire les orbital bc lose electron, so li+ is smaller (also think of it cuz lose electron, the protons redistribute pull onto remaining electrons thus pulling tighter and making smaller) higher effective nuclear charge 1. fewer energy levels 2. less shielding 3. higher effective nuclear charge

pick larger particle Sr or Sr2+ N2- or N3- O or O2- K+ or Ar

sr is larger cuz the cation loses two electrons and thus redistributes pull on electrons a sighted pull so make smaller for Sr2+ N3- cuz gain more electrons, so protons have to pull on more electrons and pull less ighy so N3- is bigger (lower effective nuc charge) O2- cuz gain two electrons , lower effective nuclear charge and have to pull less right Ar bc it has lower effective nuclear charge- they both have 18 electrons, but potassium has 19 protons to pull on those 18 so it's more tight and so K is smaller and Ar is bigger

Coulomb's Law equation Latrice energy (BIG____) Lattice energy increases as

strength of an ionic bond is directly related to the product of the ions charges and inversely related to the distance between the ions E= kQ1Q2/ R (Q 1 and Q2 are the charges, R is the distance between charge centers) big endo- the energy required to completely separate a mole of a solid ionic compound into its gaseous ions charges on ions increase, radii between ions decrease

Ionic bond involves what kind of attraction occurs btwn the ions? bond forming is always covalent involves in this, the atoms have sharing can be

the transfer of electrons from metal to nonmetal- electrostatic (attraction btwn to ions of opposite charge) exo sharing of electrons between two nonmetals smal doff electronegativity (ability to pull electrons to self when in bond) equal (nonpolar- v small diff electronegativity) or unequal (polar- large diff in electronegativity)

first ionization energy trend -top to bottom all three of those make -left to right why does beryllium have higher ionization energy than boron?

top to bottom, energy levels increase, shielding increases, ionization energy decreases it easier to remove electron and less energy required atomic number (nuclear charge) increases, making it harder to remove electron and so more energy required, shielding and energy level are constant, IE increases cuz be configuration is 1s2 2s2 while Boron configuration is 1s2 2s2 2p1, and on average p orbitals are a little further from nucleus cuz it's longer than s and its shape corresponds to 90% probability of finding electrons so p electrons are physically further- also, as second point, s electrons slightly shield p electrons so takes less energy

why are metals ductile and malleable ionic bonds get ___ as ____ goes ___ the energy of ionic bonding can be discussed through

when you apply force, metal cores move over and minimize répulsions- you don't make new répulsions, so wont crack (delocalized electrons slide around and simply shift- atoms roll over eachother (deforming force just moves atoms from one lattice site to another) stronger as charges go up and as ions themselves get closer coulomb's law and an understanding of lattice energy (direct measure of strength of ionic bond)

pi bond triple bond bond order bond order = rank in increasing bond length and strength : SiF SiC SiO

(sigma and pi) - abond that is formed when parallel orbitals overlap to share electrons- diff in strength of double bond- also have pi overlap-2 hybridized p orbitals parallel to one another pair head to head, pair p overlap in y plane, pair p overlap in z plane gives info about strength and length of bonds-(bigger bond order, stronger and shorter bond is) # e- pairs shared / # bonding sites shortest to longest- SiF(f smallest out of them), SiO, SiC weakest to strongest SiC, SiO, SiF

ionic character of bond determined by larger the electronegativity difference, ____ if a compound conducts when melted, EN difference values definition of ionic-

(unequalities of sharing) determined by EN difference between atoms more ionic character in bond (most metallic of metals (fathersst to left and down) and least metallic of no metals (farthest right and upwards of jonmetals) free moving electrons Ionic >1.7 (when melted/dissolved in water, if conduct) P.C- .4-1.7 N.P.C- <.4, ex diatomics- share v equally any binary compound that conducts electricity when melted or dissolved in water

Anion vs atom metals easily ____, cuz metals ____ to form ____ -leads to a ____ in ___ relative to the ___ -more____ than ___ Nonmetals have ____ and ___ - tend to ____ to form -leads to _____ in _____ - mor____ than ____

1. lower effective nuclear charge, same energy level, same shielding lose electrons cuz low ionization energies lose electrons to form cations (positive ions) decrease in ion size relative to the atom (effective nuclear charge increase, energy level decrease, decrease shielding) protons than electrons- protons win do ion shrinks- redistribute pull and pull tighter high ionization energies, low electron affinity levels gain electrons to form anions(negative ions) increase in ion size relative to the atom (decrease effective nuclear charge) electrons than protons- electrons win- ion gets larger

effective nuclear charge as electrons increase, (ex) A chlorine with bonding atomic nucleus

2 atoms with dame nuclear charge (p) but different number electrons effective nuclear charge decreases Zeff 17 p holding onto 17 e is much smaller than 17 p holding on to 18 e one half of the distance between covalently bonded nuclei

Resonance in benzene it is commonly depicted as a bond order

organic compound benzene, C6H6, has 2 resonance structures hexagon with circle inside to signify delocalized electrons in the ring goes double single double single double single... so take the pi bonds and switch- bond order 1.5 (draw it out izzy)

sigma bond

overlap of orbitals directly between the bonding atoms- due to nature of orbitals overlapping head to head on intermolecular axis (right between two electrons)

metalloids metallic character refers to elements become metal reactivity when exposé metal to oxygen more metallic: Rb or Cr Co or W Cl or Te

pick properties from both metals and no metals , gain or lose electrons depending on what paired with, semiconductors of heat and electricity refers to trend of having the most pronounced metal properties more metallic as they approach bottom left corner of periodic table (always Cs/Fr) shows a trend (only with alkali and alkaline earth metals tho) (goes as I.E.- as IE decreases metal reactivity decreases cuz takes less energy to remove electron so more reactive (more reactive further down and to left) react and form coating, more reactive quicker it'll form Rb, W, Te

most covalent substances are —— why? if network solid (____) , then covalent bonds have ____ ____ in these compounds, electrons are____, so but for network covalent

poor electrical conductors in all states -no ions or electrons that can move-elecs are tied in bonds-(exception acids tho-ex acetic acid-cov bond- ability dissociate and produce ions (diamond)(atoms all connected) exceeding hard (1 big molecule) weak intermolecular forced between the molecules (vander waals, dipole, hydrogen bonds) lead to ease of separating molecules (low bp, low mp, softness of solids) localized (stuck) so no conductivy possible strong covalent bonds make very strong substance

Periodicity is Trends are referred to as periodic because they ______ at ____, in much the same way that a ______, the trends ____ their ____ in ____. Factors that affect periodic properties

properties that show trends or patterns based upon their location on periodic table they repeat at regular intervals, in much the same way that a magazine (a "periodical") arrives every week, the trends repeat their patterns in predicted intervals Nuclear charge (number protons in nucleus) Electronic structure/ energy levels: size of electron cloud Shielding effect- inner shell elecs block the pull of nucleus on outer elecs

Roman numeral A elements are the tin/lead area of metals only ____, they reach a _____ Ex Pb- configuration of [Xe] 6s2 4f14 5d10 6p2

representative elements cuz represent all diff types of elements (m,nm, gases..) only lose their valence shell electrons, they reach a pseudo noble gas state knowing lead can is metal means t will lose and we know the charges are +2 and +4, so can either lose 6p2 electrons (easier to remove so first) to form Pb2+ or lose both 6p2 and 6s2 electrons (pseudo noble gas) and form Pb4+

resonance structure Bond order of O3 Bond length and bond energy measurements indicate Actual molecule is a Resonance accounts for resonance often results in ___ bond orders

same sequence of atoms but differing locations of bonds and lone pairs O=O-O (3/2 so 1.5) that the bonds of a molecules resonance structure are identical resonance hybrid (avg and/or mix of the forms) electron pair délocalisation-(usually a double bond and a single bond adjacent to one another) fractional

•What charges do we predict for elements?• "A" group elements must ex (Mg ion) Si is a ___ and can ___ ex Oxygen however chlorine when metals interact, they make

satisfy octet rule(empty or fill valence)-want to be isoelectronic with noble gas (has to do with what kind of element it is) Mg configuration is 1s2 2s2 2p6 3s2 so to get to neon configuration and since it's a metal it loses and will lose valence electrons (so 3s2) and now isoelectronic to neon (so Mg2+ ion) metalloid and can gain to lose 4 electrons cuz it is a metalloid Configuration is 1s2 2s2 2p6 3s2 3p2, so can either lose the four valence to get to noble has configuration or fill to get noble gas notation (Si 4+ or Si4-) is a nonmetal so will gain to electrons to become O2- is a nonmetal so will want to gain electrons cations based on losing electrons

exceptions to the octet rule Draw BeF2 and BH3 and look at packet free radicals usually contain an atom from free radicals have ____ electrons, so they desperately do EX of NO

B- 6 Be- 4 (nuc too small to interact w 8) Al-6 H-2 odd total electron molecules, have lone unpaired e- an odd number group, such as 5a and 7a (relate to free radicals as long as not ion) lone unpaired electron, desperately want to make it a pair, so bump into other molecules to remove electrons or atoms (best we can do cuz cant go beyond 7 for N cuz in pd 2, and in EL 2s and 2p

expanded octet -definition -it utilizes can only use in Ex XeF4 when drawing lewis structure of oxyacid, Ex H2SO4 formal charges ...

An exception to the octet rule that permits atoms in the third row or lower on the periodic table to have more than eight electrons in a Lewis structure. empty d orbitals pd 3 or beyond nonmetals-most likely p, s, cl, Br, I, Xe (p empty 3d so can fill extra polyatomic ion goes in the middle and the ionizable hydrogen atoms connect off Oxygen atoms categorize electrons brought in

Isoelectronic for alkaline earth metals, affinity for noble gases Most electron affinity 1 values are____... the _____ nucleus ... when is value positive? All ___ are always ___

having the same number of electrons is positive, cuz add to new subelvels and s orbitals shield p orbitals slightly and p physically further from nucleus on avg have a full shell- so add electrons to new one energy level- physically further and have more shielding- (reduced attraction between nucleus and electrons) favorable (electron affinity is negative and exothermic), positive nucleus attracts the negative electron, when adding electrons results in having to go to new sublevel or energy level, the value is often positive, thus unfavorable (alkaline earth and noble gases) electron affinity 2 values are always positive ( negative electron being added to already negative ion)

Why soluble p 2

Ionic solids (or salts) contain positive and negative ions, which are held together by the strong force of attraction between particles with opposite charges. When one of these solids dissolves in water, the ions that form the solid are released into solution, where they become associated with the polar solvent molecules., We can generally assume that salts dissociate into their ions when they dissolve in water. Ionic compounds dissolve in water if the energy given off when the ions interact with water molecules compensates for the energy needed to break the ionic bonds in the solid and the energy required to separate the water molecules so that the ions can be inserted into solution.

ex MgO vs NaF LiF vs KI

MgO has 4 x lattice energy cuz +2/-2 ions in MgO similar to size of ions in NaF, but Na+ and Mg2+ are isoelectronic and Na+ is smaller, both +1/-1 chargé, Li+ is smaller than K+, F- is smaller than I-, as result, ions get closer and have stronger lattice energy

Why nitrogen require more ionization energy than oxygen? Which has higher ionization energy? O or F N or P Be or B Al+ or Al2+

N configuration is 1s2 2s2 2p3 and O is 1s2 2s2 2p4, so the half full p orbital in nitrogen demonstrates symmetry and decreases overall energy of atom ( more stable when half full so require more energy) and as second point, Oxygen valence have 2 arrows (N only has one arrow for valence) and so two electrons in the same orbital have répulsions, making it easier to take away F cuz has more protons, so smaller and more tightly held, and bigger nuclear charge, so require more energy to remove N cuz has less shielding, fewer energy levels, so requires more energy to remove Be cuz P orbitals in B slightly farther away from nucleus so requires less energy to take away, and also s orbitals shield p orbitals slightly, so requires less energy Al2+ cuz lose two electrons and so redistribute pull on few electrons and so pull tighter and require more energy to take away- increases effective nuclear charge and successive ionization energies always need more energy to remove

as nuclear charge increases down a periodic table, ionization energy ____ across table cuz ionization ____ down table cuz ionization energy increases due to

hold tighter and so smaller and require more energy to remove more shielding effect and higher energy level- the added electrons make protons pull less tightly cuz blockage and less attraction increases, get smaller and require more energy to take away decreases cuz shielding and less attraction effective nuclear charge

nonpolar covalent bonds are typically lower case delta means metallic- metal atoms nuclei are an allow is a in this model, electrons are ____- metal has ____ to ____ metal cores are délocaliser electrons-

hydrocarbons diatomic molecules partial charge surrounded by a de localized sea of electrons physical mix of metals free to move and conduct heat and electricity -metal has valence elecs free to move, not tied to particular atom nucleus and inner shell electrons freedom of movement and conduct heat and electricity

paramagnetism diamagnetism example Fe2O3 IsT2+ ion paramagnetic Metals properties -color, ability, most .. delocalized electrons are nonmetals properties- color, ability, most... example no metal oxide and water nonmetallic oxide in water ... oxyanion is

a slight attraction of a substance with unpaired electrons to an external magnetic field slight magnetic repulsion that exists in substances with paired electrons fe3+ has all parallel electrons and any parallel exlectons which are un paired will make it slightly attracted to magnet but o22- has all paired electrons and so has slight répulsions yes cuz when take away valence for ion you go from [Ar] 4s2 3d2 to [Ar] 3d2 and if u draw that out there are two parallel arrows so there is slight attraction cuz unpaired electrons shiny color and various colors, though mostly silvery, malleable and ductile, good conductor of heat and electricity cuz of metallic bonding( metals have inner shell elects surrounded by délocalisés elecs) (see other quizlet) most metal oxides are ionic solids that are based (cause ph to increase), tend to form cations in aqueous solutions (cuz lose elecs) outer electrons free to move so can conduct heat and electricity no luster (dull), various colors, usually brittle, some hard some soft, poor conductors of heat and electricity (insulators), most nonmetallic oxides are molecular substances that form acidic solutions (tend to form anions or oxyanions in aqueous solution cuz gain electrons CO2 + HOH----> HCO3 decrease pH decreases pH our polatomic ions - ex chlorine plus water makes a chloride ion

Electronegativity He, Ne, Ar increase EN, EN trends to Linear molecule CO2

ability of a BONDED ATOM to attract electrons within the chemical bond don't make bonds so can't have EN pull more electrons to self, more pull away from others ( so unequal sharing and pc bond) top right corner near F, most electroneg, (greatest want for an electron when bonded) (EN increases as become smaller and have higher Z) although polar bonds? add together two vectors and cancel eachother out, so nonpolar molecule

effective nuclear charge is when

all have same nucleus (same p and n)

metallic bonding results from this bonding arises thru these bonds lead to but, metal ions arent most of these compounds have most are ___-____-____

attraction between cores of metal atoms (metal cations) and delocalized valence electrons shared pooling if valence electrons from many atoms (E sea model) crystalline solids arentkt held in place as rigidly as ionic solid(cause delocalized electrons act as lubricant and can slide around) moderate to high mp and much higher bp (break metallic bonds cause increase energy) deformable- malleable-sheets, ductile-wire(no repelling so no cleaving)

Covalent bonding results from Electron sharing occurs btwn leads to... bond length is where the ___ is ___ and the ___ is ___ most covalent compounds are ___,____,or____ these compounds have

attraction between two nuclei and a localized electron pair (they share) two nonmetals with low EN differences separate molecules with specific shapes (VSEPR) or to extended network (ex diamond) attraction maximized, repulsion minimized gases (methane and ammoni), liquids (benzene and water), or low melting solids (sulfur or wax) low boil and melt points (only weaken or break intermolecular forces)

it is insoluble if hydronium shell

bigger endo vs exo values solvent molecules surround ion/compound

covalent bonds hve no___, so they are formation of a lattice is Ionic bonding results from the ____ between electron transfer occurs btwn these bonds lead to __with ____in regular ___- which are

charged particles free to move, so don't conduct heat and elec. formation of ionic bond attraction between positive and negative ions (electrostatic attraction) atoms of large EN difference (m and nm) crystalline solids with ions packed tightly in regular array/no separate molecules exist (in a crystal of NaCl there are 1,000s of ions-no individual pairs) (lattice structures)

metallic bonds ____ and ___ in all___ metallic bond properties are explained by melting- ____ boiling- more ____ in metallic bonds account for malleability/ductility-

conduct heat and electricity in all states (valence e free to move) regularity of metal-ion array and mobility of valence electron electrostatic attractions not broken-(why it is moderate mp) electrostatic attraction must be broken (whyhave very high bp) valence electrons- higher bp and mp, better conductors heat and electricity (cuz mobile e-) electron sea keeps bonding structure intact-no repulsions

IE1 left to right a big jump is metals require

nuclear charge increases, energy level and shielding stay constant change in energy level, and decreases shielding so way harder to remove- and also at noble gas state so full valence and make super hard to remove cuz stable and want to keep them less ionization energy than nonmetals- nonmetals want to gain electrons so takes way more energy to remove, but metals want to lose electrons so easier

the strength of a bond is measured by this energy is referred to as ex a bond energy table lists Avg bond energies are always Breaking bonds: Forming bonds: calculate heat of reaction using Bond energies so sum of is O2- or Cl- smaller and why? LOOK AT EX

determining how much energy required to break the bond (endo cuz put in energy to break bond) (form bond is exo) bond energy (enthalpy) for CL-CL bond, if right frequencies are met, can cleave bond (resulting atoms to make free radicals) look at EXAMPLE! lists avg bond energies for many diff types of bonds positive, cuz bond breaking is endothermic process (must input energy) put energy in so delta H + release energy so delta H - enthalpy of reaction = enthalpy of bonds broken (endo) (only positive) (show up as reactants) - enthalpy bonds formed (exo so neg number, but it's - (-) so positive )(products) heat of formation of products - heat of formation of reactants, OR energies of broken bond (positive) - energy of bond formed (turns out to be positive cuz -(-)) O2-, cuz it is isoelectronic to neon while Cl- is isoelectric to argon, and neon is a lesser energy level so less shielding and is smaller

bond length is bond length is determined by ____, but also ____ if you bring atoms too close, generally tho, as two atoms get closer, describe graph below 0,

distance where attractive and repulsive forces are balanced- where maximized attractions and minimized répulsions attractions but also répulsions they have to one another répulsions can out weigh attraction attractions outweigh repulsions as atoms get closer, attraction outweighs repulsion, and atoms come closer and decrease in PE, and then energy at the minimum is the sweet spot- where repulsions and attractions are balanced- that's ur bond length- cuz if start to get too close, then repulsions outweigh attractions and Pe increases (but to be stable compounds like low PE) forming bond is exo

when atoms of different EN bond,____ are ____. The bond that is produced has___ and ___ and is called a Polar bonds can be represented in two ways ex to be polar:

e- are shared unequally partially positive and negative poles called a polar covalent bond Arrow with plus thingy on end-(more positive at plus end more negative at arrow tip) or lower case deltas (partial positive and partis negative charge) for water, H2O, the tips (-) part of arrow points towards O, and the plus parts point towards two hydrogen's (H and O have diff EN so polar cov bond, and water shaped like triangle so polar arrows don't cancel bonds that r polar, arrows that don't cancel one another out H bond- very strong dipole dipole-it's strongest cuz H and O are very small and very polar cuz O v electronegative

each element displays unique gas phase emission spectrum DO THE PRACTICE STUFF!!

each element has unique electron configuration with unique energies for its particular shblevels due to diff in Z, EL, and shielding- this unique e- transmission correspond to each element, giving unique spectrum.

electron affinity is the ____- it can be attraction to nuclei electron affinity one: Electron affinity 2: when bringing substances together,

energy change accompanying a mole of electrons being added to a mole of gaseous atoms or ions, endo or exo gives off energy USUALLY exo, - atom + e- —-> Ion- ALWAYS ENDOTHERMIC!!!! cuz 2 negative particles when close tg repel, so you have to push tg and our energy in for it to happen- same with 2nd, 3rd, 4th... Ion- + e- —-> Ion2- every bond forming process is exothermic

atomic radius trend top to bottom, left to right, arrange C, H, F in order of i creasing size ionic radii are to _____ as atomic radiii are to ___

energy levels are going up, shielding increases, meaning more innershell electrons (both cause atom to become larger) (since add more electrons, protons have less attraction to nucleus cuz shielding so bigger) nuclear charge increases, causing atoms to shrink cuz more protons pull on electrons H (furthest left) F (greater atomic number) C charges, neutral

giving an electron is ___and give back is ___ Ionization energy is IE involves.... so the process is ____ First ionization energy (definition and equation) Second energy level IE1 and IE2 are referred to as

exo, give back is endo amount of energy needed to completely remove one mol of electrons from one mol of gaseous atoms or ions putting energy into the atom, so the process is endothermic and the values are positive energy needed to remove outermost electron from atom (easiest electron to remove) energy + atom—-> Ion+ + e- amount of energy needed to remove second electron from same atom (always larger than first ionization energy) energy + Ion+—-> Ion2+ + e- successive ionization energies (always become more endothermic (higher nuclear effective charge aka more difficult to remove)

the more atoms attract, expect moving across periodic table, bonds bond energies are always Covalent bond- mutual there are 2 ____ single bond double triple

expect shorter bond so stronger bond get shorter, cuz atoms get smaller (so therefore stronger) positive cuz endo and require energy to break attraction of nuclei and electron pair, resulting in shared electrons 2 pair electrons sitting in between nuclei one pair shared between nuclei 2 shared pairs between nuclei 3 shared pairs between nuclei

properties of ionic bonds : ___,___,___(cuz...), no ______ but ______, ____ and ____ powerful____ hold ____ (resists___) moving ions out of position requires if enough ___ is ___, ions of ___ will___, thus..

hard(crystal- ions don't budge), rigid(lattice), brittle (cuz when ions move they repel), no conductivity in solid state(cuz ions held too tightly and cant move), conductivity in aqueous solution and molten state(cuz can move and conduct), high melt and boil pt (require you to break ionic bonds- attractive forces hold ions in place throughout the crystal(melt and boil- weaken and break bonds) overcoming the forces (sample resists being dented or cracked) pressure is applied to overcome attraction, ion of like charges are brought close tg, their répulsions crack the sample -cleave

why are ionic bonds brittle -ions resist ionic compounds often ——why are compounds that contain ionic bonds often soluble in water?—— for an ionic substance to dissolve 1 2 3 4 all these combine to greater electronegativity has

if put in enough force, can move ions, now have répulsions, répulsions cause shatter or cleave -movement, but if do move repel and cleave soluble in water- when they do dissolve in water can conduct heat and electricity break or separate the lattice (endo cuz cost lots of energy to separate) when ionic compound in water, dissociates, ions sep from one another they're soluble bc water is polar, and so it's partially positive hydrogen ends are attracted to the negatively charged anions within an ionic bond and the partially negative Ocygen in water is attracted to the cations within the compound, so as the water molecules surround the ions you form hydration (or solvation if solvent isn't water) shells-when u have solvent molecules surrounding particular ions-and then hydrated ions are ripped away into the solution 1 separate solute( break lattice) (have to be able to overcome ionic bonds, 2- create separations in solvent- have to overcome H bonding aka attractions between water molecules-endo(create pockets in water for ions cuz overcome hydrogen bonding- which are especially polar bonds cuz large diff electronegativity (unequal share) also O and H are smal so allow one dipole and another dipole to get close, so stronger attraction), the. mix solute and solvent, create ion dipole forces (exo)- and solutions are more disorder than pure substances-favorable entropy of mixing -weigh all these components tg and when something dissolves it is favorable. find delta H of solution-whether mix it up make solution hot or cold greater ability to pull elecs to self (smaller and higher Z)(F,N,O v electronegativity)

Atomic number from left to right, Top to Bottom Energy levels _____ ____ (____ from ____, has ____ on how well _____ to ____< less ___) Shielding effect (calculate by) also... Shielding effect has Nuclear Charge (___) vs Effective nuclear charge (Zeff)

increasing atomic number, hold electrons more tightly, so smaller. Atomic number increases, (generally unimportant compared to nuclear charge), Left to right, energy levels stays constant Top to bottom, energy levels get higher (further from nucleus, has affect on how well electrons held to nucleus, less tight) total elecs- valence= shielding elecs top to bottom, increases cuz adding inner shell electrons, left to right- constant mini repulsions (nuclear) Na vs Mg- na has nuc charge of 11, Mg has nuc charge of 12- different elements with different atomic numbers and different pulls Cl vs Cl- (EFFECTIVE) Cl:P+= 17, E-= 17 Cl-: 17p, 18 e-, 17 elecs pull on 17 protons, different than 17 protons pulling on 18 electrons

isoelectric series ionic size ____ with an ___ Na+ vs Na Na+ vs Mg2+ vs Al3+ vs O2- vs F-

ions and atoms with same number electrons, different number protons decreases with increasing nuclear charge Na + cuz has 11 protons, 10 electrons all 10 electrons- sodium has the 11 protons, magnesium with 12, aluminum with 13, oxygen with 8, fluorine with 9—- aluminum ion is smallest cuz increase number protons greater pull on electrons (highest atomic number) and oxygen largest cuz least protons pulling electrons (so electrons less tightly held and further away)

transition metals lose ____- often stop at ____ ex:Fe with configuration [Ar] 4s2 3d6 Ag... ex for metalloid arsenic

lose their s electrons first ( cuz s are their valence) followed by some number of d electrons- a stable d configuration arsenic can form 3 charges- As5+, As 3+, As3-, column 5, 5 valence, lose p, or gain 3 or lose 3 loses 1 bc only has one valence can form 2 and 3, so first lose 4s to make Fe2+, then lose 4s and 1 from 3d to make Fe3+ (that gives one arrow in each of five orbitals so more stable and have symmetry

only definitive way to determine if compound is ionic Lewis structure represents In the lewis structure of a molecule or poly atomic ion, two kinds of pairs Rules resonance structures are never Do EXAMPLES!

melt and see if conducts electricity the bonding pairs and lone pairs in a molecule valence e- occur in pairs Bonding pair- exist btwn two atoms of the compound-can be represented by straight line btwn the bonded atoms lone pair- belongs entirely to one atom -represented by pair of dots on that atom H cant be center, must be terminal- C is always center cuz makes most bonds (4), least electronegative in center, exactly same as ones you draw- mix of the ones you draw- the most accepted/favorable resonance resembles the actual structure the most (90% or so)

metals form ____ that act as ___ the pH ____ because of the ____ Nonmetals form weak acids have nonmetals have very low Nonmetal reactivity goes as What is most reactive nonmetal?

metallic oxides that act as bases in water (CaO + HOH ---> CaOH2 + H2 (g) rises cuz of the aqueous base dissolving there will be dissociation of ions and so presence of dissociated OH- ions increase pH nonmetallic oxides that act as acids in water (ex Co2+H2O—-> H2CO3 (aq) little dissociation metallic character Electron afffinity (as EA increases, reactivity if nonmetal increases) fluorine

left to right is based mostly on top to bottom based mostly on left to right, atoms get there is an overlap of

nuclear charge energy level/shielding smaller cuz nuclear charge has greater effect than shielding and adding more protons makes more attracted to electrons electron clouds where a bond is