inorganic chemistry chapter 9
bonding trends in hydrides of 2nd and 3rd periods
- formulas of hydrides correspond with lowest common oxidation state of the non-hydrogen element -nonmetal hydrides are small, covalent molecules with very low boiling points -all are gases at room temperature except water and HF( these two are liquid at room temperature)
write formulas for period 4 main group metal fluorides and identify bonding type.
-KF=ionic -CaF2=ionic -GaF3=covalent -GeF4-covalent -AsF3/5=covalent -SeF6=covalent
write formulas for period 4 main group metal hydrides and identify bond type.
-KH=ionic -CaH2=ionic -GaH3=covalent -GeH4=covalent -AsH3=covalent -HBr=covalent
phosphorus V and vanadium V
-P is a nonmetal -V is a metal - similarities in +5 oxidation states -both form a large number of polymeric anions -phosphate and vanadate ions are both strong bases -but at low pH vanadate turns into vanadyl
what are common features of alum?
-are crystalline solids with each metal ion surrounded by 6 water molecules - are soluble in hot water and insoluble in cold water -their air solutions are acidic due to salt hydrolysis -show isomorphism(similar cyrstalline structures) -very stable due to high lattice energy
Li and Be
-both are metals -both are shiny and good electrical conductors -Li has a low melting point -Li has high reactivity -Be has a high melting point due to a strong metallic bond
compare and contrast chemistry of silver(I)/Ag^+ and rubidium/Rb
-both form +1 ions of their salts -silver hydroxides are insoluble in water, while rubidium hydroxides are soluble in water -silver halides are insoluble in water, while rubidium halides are
chlorine VII and manganese VII
-both form strongly oxidizing oxoanions -form isostructural salts -oxoacids are strong -ions different in color( permanganate is purple while perchlorate is colorless) -chlorine has colorless oxides while manganese has reddish brown oxides -both oxides highly explosive at room temperature -form +4 oxidation state oxides (ClO2 and MnO2)
antimony and bismuth characteristics
-both gray solids -similar solid state structures -metallic bonding -have characteristics of metals -both form salts and cations -weak metals since they sometimes form oxoanions
magnesium and zinc
-chlorides and sulfates are soluble -carbonates insoluble -zn is amphoteric so its hydroxide will dissolve into zincate ion in strongly basic solution
graphite
-common form of carbon -sublimes at 4000 C -nonmetal that has layers of multiple bonds -high melting point due to network covalency
Boron
-dark red -poor electrical conductor -classified as a metalloid -has linking covalent bonds -high melting point
trends in third period
-first 3 elements have metallic bonding - silicon has network covalent bonding -nonmetals don't show multiple covalent bonds in their common forms -Cl is a simple covalent diatomic molecule with low melting point -Ar is a monoatomic gas and has the lowest melting point in the period
N, O, and F characteristics
-form diatomic molecules -held together by covalent bonds -low melting points due to weak dispersion forces -prefer multiple bonding -dinitrogen has a triple bond -dioxygen has a double bond -diflourine has a single bond - neon gas is monoatomic
differences of beryllium and aluminum
-formula of hydrated ions; Be hydrated ion has lower coordination number than Al due to Be cation being 2 small to accommodate 6 water molecules
Arsenic characteristics
-gray solid -contains network covalent bonding -sublimes directly into gas phase when heated strongly -forms stable oxoanions like arsenate
yellow sulfur
-has 8 sulfur rings held together by single covalent bonds
similarities of boron and silicon
-has covalent bonding chemistry -both on ionic/covalent borderline -similar electronegativities -both form solid acidic oxides -both form very weak acids -both form numerous polymeric ions with similar structures -both form flammable, gaseous hydrides
sulfur VI and Chromium VI
-has some formula similarities -oxychlorides sulfuryl and chromyl both soluble in water -chromates and dichromates strongly oxidizing and colored -sulfates and pyrosulfates are non-oxidizing and colorless -oxoacids are strong with sulfur being the strongest
tin and titanium
-has the closest similarities of elements in different groups -form isostructural oxides -both turn yellow upon heating -close melting and boiling points of chlorides -both form chlorides that act as Lewis acids and hydrolyze in water
alkali metals and coinage metals
-have no major similarities -dissimilarity of metallic behavior -alkali metals are reactive and all common salts are soluble -coinage metals are nonreactive and most of their +1 oxidation state compounds are insoluble
trends of highest oxidized fluorides with period 2 and 3 elements
-is a transition from ionic to covalent -network covalent region that marks a divide between ionic and covalent -formulas rise to a max element-F ratio at carbon then decrease ( elements in 2nd period limited to 8 electrons) -oxidation number increases steadily until sulfur
N2 characteristics
-nonmetal -colorless -low melting and boiling points due to weak dispersion forces -N2 gas unreactive -forms stable oxoanions like nitrate
uranium (VI) and group 6 metals in +6 oxidation state
-oxoanions of uranium and dichromate ion -uranyl chloride matches chromyl chloride and molybdenum chloride -uranium and tungsten form stable hexachlorides -resemblance results from similarities in outer electron configurations -f orbitals in tungsten and seaborgium are buried while those of uranium are part of valence shell -partial occupancy of 5f and 6d orbitals suggest they are of similar energies -uranium readily attains +6 oxidation state like group 6 elements
kinghts move similarities of Zn II and tin II
-produce insoluble hydroxy-chlorides -form chloro-complexes -both amphoteric
lanthanoid relationships
-progression of series corresponds to successive filling of 4f orbitals -common oxidation state results from the balance between ionization energy of metal and lattice energy of solid salt formed -optimum reduction in renergy coresponds to formation of 3+ ion -remaning 4f orbitals are ''buried'' -lanthanoids behave like large main group metals having a +3 oxidation state which most closely resembles group 3
kinghts move similarities of tin IV and polonium IV
-several formulaic similarities -solid stable nitrates -matching +4 oxides
similarities of beryllium and aluminum
-similar charge densities -in air, both metals form tenacious oxide coatings that protect interior of metal sample from oxidation -both are amphoteric , forming parallel anions -both form carbides
knights move similarities of silver I , thallium I, and potassium
-similar toxicity in Tl and K ions -Tl and Ag found in same lattice site -Tl can also use K transport system in cell
Xe VIII and Osmium VIII
-similarities in +8 oxidation state -both form yellow +8 oxides -similar formulas of oxyfluorides _in +6 oxidation state, both form their highest fluoride oxides and both form fluoroanions
compare and contrast the chemistry of manganese (VII) /Mn^7+ and chlorine (VII)/ Cl^7-
-the oxyanions of both are strong oxidizing agents - their salts are isostructural -permanganate ion is purple while ClO3 ion is colorless -chlorine oxides are colorless, while Mn oxides are reddish brown
aluminum and scandium
-they are so similar that it has been suggested that Al actually belongs in group 3 -Al ion has a noble gas configuration like the 3+ ions of group 3 while group 13 elements have filled d¹⁰ orbitals -both hydrolyze to give acidic solutions -both produce hydroxide solids -both form isostructural compounds of the type Na3MF6
in group 14, which element is most likely to have an extensive cation chemistry and readily form an oxoanion?
-to have mostly cation chemistry , element must have a metallic character, such as tin or lead. -forming oxoanions is a characteristic of weak/borderline metals
allotrope of phosphorus
-waxy,white solid -contains clusters of 4 atoms(P4 units) bound by single covalent bonds
similarities of lithium and magnesium
1. hardness 2. forms normal oxides 3. forms nitrides 4. salts have low solubility 5. forms organometallic compounds 6. high degree of covalency 7. carbonates decompose to give metal oxide and carbon dioxide 8. charge density
what are the 3 pairs of elements in which the diagonal relationship is most significant?
1. lithium and magnesium 2. beryllium and aluminum 3. boron and silicon
explain why aluminum might be considered a member of group 3 instead of group 13.
1. physical properties of Al resemble those of group 3 more than group 13 2. Al has a high reduction potential like group 3; the Al³⁺ ion has a closed shell electron configuration like that of group 3 and unlike lower members of group 13 that have completely filled d-orbitals 3. like Sc, the Al ion undergoes hydrolysis in water 4. there are several isomorphous compounds of Al and Sc
what is meant by the knight's move?
2 elements that are 1 period down and 2 groups to the right(L shape) share similar oxidation states and other properties
similarities of europium (II) and strontium
2 exceptions to simplicity of lanthanoids; 1st is Eu. it readily forms a 2+ ion due to stability of half filled f orbital set([Xe]4f⁷); ionic radius is similar to strontium -several compounds are isostructural
write the formulas of aluminum oxide and scandium oxide
A.) Al2O3 b.) Sc2O3
why is the melting point of Ne less than those of N, O, and F?
N,O, and F can all form multiple bonds and exist as diatomic molecules in nature. But Ne is monoatomic and so it has the weakest dispersion forces.
write the formulas of two oxoanions that seaborgium might form
Sg2O7 and HgO4-
titanium (IV) nitrate shares many properties, including identical crystal structure, with a metal of a different group. identify the metal.
SnO2
for tellurium , Te, what is likely to be the highest formula fluoride?What is the formula of the hydride? what phase would you expect these compounds to be in at room temperature?
Tellurium is in group 16, thus TeF6 should be the highest fluoride. The hydride will be TeH2. both of these compounds will most likely be gases
across second period, the trend in melting point is
a rapid increase than an abrupt decrease
carbon and nitrogen form the cyanide ion, CN^-. write formulas of isoelectronic species of a.) Carbon with oxygen and b.) carbon with carbon
a.) CO b.) C₂²⁻
write the formulas of oxyanions of phosphorus and vanadium in their highest oxidation state.
a.) P4O₁₂⁴⁻ b.) VO₄³⁻
write a chemical equation for the reaction of water with solid sulfur trioxide and with chromium (VI) oxide.
a.) SO3(s) + H2O(l) -> H2SO4 (aq) b.) CrO3(s) + H2O (l) -> H2CrO4(aq)
write a chemical equation for the reaction of water with liquid silicon tetrachloride and titanium(IV) chloride.
a.) SiCl4(l) + 2H2O (l) -> Si(OH)4 (aq) -> Heat-> SiO2 (s) b.) TiCl4 (l) + 2H2O (l) -> TiO2(s) + 4HCl (aq)
If calcium hydride is melted and electrolyzed , what are the products as the a.) cathode b.) anode?
a.) calcium is deposited/Ca^2+ + 2e^--> Ca(s) b.) hydrogen gas is released/2H^- -> H2(g) + 2e^-
What are the formulas of the highest oxidation state oxide of chlorine and manganese? what other oxides of these two also have similar formulas?
a.) highest oxides of chlorine; Cl2O7, Cl2O6 b.) highest oxides of manganese; Mn2O7 -others are ClO2 and MnO2
the knight's move relationship exists when both elements are in the same oxidation states. which oxidation would be shared by a.) indium and copper?b.) cadmium and lead?c.) indium and bismuth?d.) zinc and tin?
a.0 +1 b.) +2 c.) +3 d.) +2
some diagonal relationships can be found elsewhere in the periodic table. suggest the formula of a rhenium ion valence isoelectronic with that of [Mo2Cl8]²⁻
as rhenium has 1 more d electron than molybdenum, to be valence isoelectronic, the ion would have one less charge per rhenium. thus the ion would be [Re2Cl8]²⁻
trend in highest oxyacids of 3rd period
as the number of electrons on central atom increases by 1, the charge decreases by 1. ex: SiO₄⁴⁻⁻, PO₄³⁻, SO₄²⁻, ClO₄⁻
explain why cerium has an oxidation state of +4 in terms of orbital occupancy.
cerium attains noble gas configuration after losing all its valence electrons, so it becomes more stable
combo elements
combination of n-x group elements with n+x group elements that form compounds parallel to those of group n
for alkali metals, melting point and boiling point ______ down the group
decrease
in group 17, reactivity______ down the group.
decreases
why do melting and boiling points increase down the group in group 17?
dispersion forces increase as the number of electrons increases.
trend of melting point in group 14
doesn't have a trend; carbon and silicone have high melting points; others show a general decrease down the group
what are the trends in melting point for group 2?
doesnt have a clear trend;
what is a trend found in group 15?
elements shift from nonmetallic to metallic behavior which is similar to that found in groups 13 through 16
explain the nonexsistence of chlorine heptaflouride
fitting 7 F atoms around a central Cl atom is impossible due to steric hindrance
suggest ions of other elements whose chemistry might match that of an ion of lead.
from the knight's move relationship, cadmium, Cd²⁺, of group 12 would be likely to share aspects of chemistry with the lower oxidation state, Pb²⁺, of group 14. in addition, there may be similarities with calcium, Ca²⁺, of group 2. ( in fact, apart from some chemical similarities, it is of note that both cadmium and lead (II) are highly toxic. Lead (II) incorporates in bone, substituting for calcium ion.)
sodium is the only alkali metal for which Na2O2 is the most stable oxide species. deduce the alkaline earth metal that also forms a stable dioxide compound.
generally, Na forms peroxide when burnt with oxygen. similarily alkaline earth metals also form peroxides with oxygen; 2MO + O2 -> 2MO2 where M can be Sr, Ba, or Ra; excepting Be and Mg all oxides show O₂²⁻ peroxides.
in group 17, melting and boiling points ______ down the group
increase
as number of electrons increases, strength of dispersion forces also _________
increases
in group 1, reactivity _______ down the group
increases
across the period, there is an observable trend in characteristics as they shift from ________, to __________, to _________.
ionic, network covalent, covalent
inert-pair effect
ions of similar charge and size (charge densities) are likely to have similar chemistry
beryllium aluminum silicate
is the mineral gemstone beryl
calcium aluminate
major component of cement
what is the trend for melting point in group 17?
melting point decreases down the group
explain trends in the melting points of the following period 2 metal oxides; MgO=2800C CaO=1728C SrO=1635C BaO=1475C
melting point decreases due to increasing atomic radius which causes decreasing strength of metallic bonding
why do ionic compounds have a high melting point?
melting process involves breaking ionic bonds in crystal lattice; ionic compounds usually have high lattice energy and ionic bonds require a lot of energy to break
what is meant by n group and n+10 group?
n and n+10 group elements have similar properties such as chemical formulas, structures, and oxidation states
there are similarities in chemical formulas and structures of the highest oxidation state of some members of the _____ group elements and of the members of the corresponding ________ group elements
n, n+10
In terms of orbital occupancy , why does europium have the oxidation state +2?
oxidation numbers of transition elements are generally +3, but some are +4. Eu's electron configuration becomes half-filled after losing its 2 6s2 electrons. The half-filled configuration provides extra stability to ion due to symmetry.
electrolysis
reactions in nature that are non-spontaneous have to be forced to proceed by applying electric current
why do transition metals form compounds in a lower than expected oxidation state from group number and why is that oxidation state always less by 2?
relativistic effects that result in orbital shrinkage and higher ionization than expected; the higher ionization energy leads to decreased stability of ionic state and hence the stabilizing of ionic oxidation state
the fluoride ion can substitute for the oxide ion in oxoanions. construct the formulas of 3 possible fluoro-oxosulfur compounds isoelectronic with the sulfate ion.
replacing an oxide, O²⁻, with a F- in the sulfate ion will result in a reduction of charge by 1 with every replacement. thus the isoelectronic series will be: SO₃F⁻, SO₂F₂, and SOF₃⁺
which metal hydroxide is isostructural with aluminum hydroxide?
scandium hydroxide
diagonal relationship
similarities in chemical properties between an element and ones to the lower right of it. this relationship is predominantly shown in the upper-left corner of the periodic table
why does Li have a low melting point?
since it has a larger atomic radius so its metallic bonding is weak resulting in an low melting point and
non-metal hydrides
small, covalent molecules with very low boiling points and melting points
monazite, MPO4, typically contains about 3% of a group 3 metal ion. guess its identity.
some d-block elements show similar properties with f-block elements; elctron configuration of Hg is [Kr}4f^12 5d^2 ^s^2, while thorium is [Rn]6d^26s^2. Both have some valence electrons and show a +4 oxidation state. Due to this, Hg is associated with thorium.
isoelectronic species
species that share the same total number of valence electrons and the same total sum of electrons ( when species have the same number of valence electrons but a different number of total electrons they are valence isoelectronic)
silver bromide's melting point is 420 degrees Celsius. Which bromide would have a similar melting point?
thallium bromide (480 C)
trends in the formulas of highest oxides in 2nd and 3rd periods tend to correlate with
the group number of the non-oxygen element; Group 1 has highest oxide of +1, group 2 has highest oxide of +2, and so on - exception is oxygen diflouride, which is the only oxide whose nonoxygen element has a higher electronegativity than oxygen -there is a diagonal band of network covalent compounds separating ionic and covalent just like with the fluorides
why does melting and boiling points decrease descending down group 1?
the metallic bonds become weaker as the atomic radius of the alkali metals increases.
write the formula of 2 ions which are isoelectronic with silicon tetrachloride
the neighboring elements are aluminum and phosphorus. to match electron total of SiCl₄, Al ion will need one more electron, while phosphorus needs one less. Thus the ions will be AlCl₄⁻ and PCl₄⁻
combo elements
the sum of the valence electrons of a pair of atoms of one element matches the sum of the valence electrons of 2 horizontal neighboring elements; the combination of an n-x group element with an n+x group element to form compounds that parallel those of the n group element
early actinoid relationships with transition metals
there are similarities in chemical formulas and chemical properties between early members of the actinoid series and the corresponding members of the transition metal series
knight's move relationship
there is a similarity between an element of group n and period m with the element in group n+2 and period m+1 in the same oxidation state. found among elements in lower right portion of periodic table
write the formulas of a metal compound analogous to ClO3F and BrO3F.
using n and n+10 concept, Mn of group 7 is likely to form an analogous compound, which would be MnO3F
two elements with stable isotopes-one a metal and one a nonmetal -form a compound XF7. suggest identity of the two elements.
using n and n+10, the 2 elements are likely to be in groups 7 and 17. for 7 bonds to the central atom, the atom size must be large. technetium, Tc, and astatine, At are disqualified as they only have radioactive isotopes. thus, the 2 elements are likely to be rhenium and iodine, which makes the compounds ReF7 and IF7.
phosphorus forms an oxychloride of formula POCl3. which transition metal is likely to form an oxychloride of matching formula?
vanadium/VOCl3
the melting points of network covalent compounds has the tendency to be
very high
the melting points of small covalent compounds tends to be
very low due to weak IMF
suggest an explanation why: a.) zinc and tin(II) have a resemblance: b.) tin (IV) and polonium (IV) have a resemblance.
zinc (II) has the noble gas configuration of [Ar]3d¹⁰, while that of tin (II) is [Kr]4d¹⁰5s². the two s electrons of tin act as an ''inert pair'', thus stabilizing the + 2 oxidation state of tin. tin (IV) has the noble gas configuration of [Kr]4d¹⁰5s², while that of polonium (IV) is [Xe]4f¹⁴5d¹⁰6s². the 2 s electrons of tin act as an ''inert pair'', thus stabilizing the +4 oxidation state of polonium.
