Periodic Trends
Which atom is larger, Ga or As?
Ga radius is larger (atomic radius decreases across the period and increases down the group).
What is a complex?
A complex is a species consisting of a central metal atom or ion to which a number of molecules or ions are attached by coordinate covalent bonds.
What are isomers?
Isomers are compounds that contain the same numbers of the same atoms but in different arrangements.
What is alpha particle?
24He
What is beta particle?
-10B
What is Electronegativity? Which element is more electronegative, Sn or O?
Electronegativity is the tendency of an atom to attract electrons to itself.
O is more electronegative (electronegativity increases across the period and decreases down the group)
In a complex, what is the primary valence? secondary valence? coordination sphere?
Primary valence - oxidation # of metal ion
Secondary valence - coordination number
Coordination sphere - the metal ion and the ligands together
What are structural isomers? What are stereoisomers?
Structural isomers are the isomers in which the atoms are connected to different partners.
Stereoisomers are isomers in which the atoms have the same partners but are arranged differently in space.
What type of nuclear reaction will the following nucleus undergo 614C?
Neutron rich, therefore it undergoes beta particle emission.
What type of nuclear reaction will the following nucleus undergo 1529P?
proton rich, therefore it undergoes positron emission or proton emission or electron capture.
What is Electron Affinity? Which element has greater electron affinity, Br or Cl?
Electron affinity, Eea, of an element is the energy released when an electron is added to a gas-phase atom.
Cl has greater electron affinity (Electron affinity increases across the period and decreases down the group)
Name the following coordination compound: K3[FeBr4(ox)]
potassium tetrabromido(oxalato)ferrate(III)
How many possible isomers are possible for [RuBr2(NH3)4]2+?
2 geometrical isomers: cis- and trans-
What type of nuclear reaction will the following nucleus undergo 92238U?
alpha and beta emissions
What is nuclear fission? and nuclear fusion?
Nuclear fission is the fragmentation of larger nuclei into smaller ones.
Nuclear fusion is when light nuclei fuse together to form heavier nuclei.
What is Polarizability? Which of the following species has the greatest polarizability, Cl-, Br, Br-?
Polarizability is the ease with which an electron cloud of an atom can be distorted by charges on neighboring groups.
Br- has larger size (polarizability decreases across the period and increases down the group. Also the anion is more electron rich).
Give the formula of the following coordination compound: triamminediaquabromidocobalt(III) hydroxide
[CoBr(NH3)3(OH2)2](OH)2
How many isomers are possible for [Cr(NH3)5(NO2)]Cl2?
two linkage: -NO2 and -ONO
and
one ionization: [CrCl(NH3)5]Cl(NO2)
A radioactive isotopes half-life is 20 days. How long it will take to decay to 87.5%?
3t1/2 = 3 x 20 d = 60 days
Complete the following equation for the nuclear transmutation:
95241Am + ? -> 4 01n + 100248Fm
511B
What is Ionization Energy? Arrange the following elements in order of increasing first ionization energy: O, Te, Se.
Ionization energy, I, is the minimum energy needed to remove an electron from an atom in the gas phase.
Ionization increases across the period and decreases down the group, so the order is Te < Se < O.
The complex [Fe(OH2)6]3+ absorbs light of wavelength 700 nm. What is the value (in kJ/mol) of ligand field splitting? What is the color of the complex?
171 kJ/mol
Green
Compare the magnetic properties of [Ni(en)3]2+ and [Ni(OH2)6]2+.
Because Ni2+ electron configuration is [Ar] 3d8 , both complexes have t2g6eg2 configuration, so both complexes have 2 unpaired electrons, therefore they both are paramagnetic.
A piece of wood, found in an archeological dig, has a carbon-14 activity that is 62% of the current carbon-14 activity. How old is the piece of the wood? Carbon-14 has a half-life of t1/2 = 5730a.
4000 a
Define binding energy. How do you calculate it?
Binding energy is the energy released when protons and neutrons come together to form a nucleus.
Ebinding = - (delta m) c2