Chemistry Test #2 (Chapters 2.14, 3, 4, 5.1-5.4)
Calculate the overall energy change in kilojoules per mole for formation of CsF(s) from its elements using the following data: Eea for F(g) = -328 kJ/mol Ei1 for Ca(g) = +375.5 kJ/mol Ei2 for Ca(g) = +1145 kJ/mol Heat of sublmation for Ca(s) = +178.2 kJ/mol Bond dissociation energy for H2(g) = +435.9 kJ/mol Net energy change for the formation of CaH2(s) from its element= -186.2 kJ/mol
-325 kJ/mol
Draw an electron-dot structure for carbon dioxide, CO2
.. .. O=C=O .. ..
What groups lose electrons to gain noble gas configuration?
1A & 2A
Group 3A has how many valence electrons and bonds?
3;3
Group 4A has how many valence electrons and bonds?
4;4
Given the following information, construct a Born-Harber cycle to calculate the lattice energy of CrCl2I(s): Net energy charger or the formation of CrCl2I(s) = -420 kJ/mol Bond dissociation energy for Cl2(g) =+243 kJ/mol Bond dissociation energy for I2(g) = +151 kJ/mol Heat of sublimation for I2(s) = +62 kJ/mol Heat of sublimation for Cr(s) = +397 kJ/mol Ei1 for Cr(g) = +652 kJ/mol Ei2 for Cr(g) = +1588 kJ/mol Ei3 for Cr(g) = +2882 kJ/mol Eea for Cr(g) = -349 kJ/mol Eea for I(g) = -295 kJ/mol
5295 kJ/mol
Group 5A has how many valence electrons and bonds?
5;3
Group 6A has how many valence electrons and bonds?
6;2
What group gains electrons to reach noble gas configuration
6A & 7A
Group 7A has how many valence electrons and bonds?
7;1
Group 8A has how many valence electrons and bonds?
8;0
What is the difference between a covalent bond and an ionic bond? Give an example of each.
A covalent bond result when two atoms share several (usually two) of their electrons. An ionic bond results from a complete transfer of one or more electrons from one atom to another. The C-H bond is methan (CH4) are covalent bonds. The bond NaCl (Na+Cl-) is an ionic bond.
Define Covalent bonds
A covalent bond results when two atoms share several (usually 2) electrons
Name AlCl3
Aluminum Chloride
Define Ionic bonds
An Ionic bond results when a complete transfer of one or more electrons from one atom to another occurs, resulting in the formation of two charged particles called ions
How can you determine an atoms radius?
An atoms radius is half the distance between the nuclei of two identical atoms when they are bonded together in chemical compounds.
What principle states that lower energy orbitals fill before higher energy ones and an orbital can hold only two electrons, which have opposite spins
Aufbau Principle
Name BaCl2
Barium Chloride
Why does the atomic radius decrease going across a row?
Because there is an increase in effective nuclear charge caused by the increasing number of protons in the nucleus
Where are elements likely to be more cation like?
Bottom left of the periodic table
What is the electron configuration of Ca^2+? What is the electron configuration of Ti^2+?
Ca^2+, [Ar] Ti^2+, [Ar] 3d^2
Name CaBr2
Calcium Bromide
CrCl3
Chromium (III) Chloride
Which of the following compounds would you expect to to be ionic and which molecular (covalent) a) BaF2 b) SF4 c) PH3 d) CH3OH
Compound a is composed of a metal (Ba) and a nonmetal (F) and is likely to be ionic. Compounds b-d are composed entirely of nonmetals and are likely to molecular
Define Binary ionic compounds & how do you name them?
Compounds made of only two elements ; they are named by identifying first the positive ion and then the negative ion. The positive ion takes the same name as the element, while the negative ion take the first part of its name from the element and then adds the ending -ide
Name CuCO3
Copper (II) Carbonate
What is the most common type of bond?
Covalent
There are two elements in the transition metal series Sc through Zn that have four unpaired electrons in their 2+ ions. Identity them.
Cr^2+, Fe^2+
What element has the greatest atomic radius?
Cs
Cu+ has an ionic radius of 77pm, but Cu2+ has an ionic radius of 73 pm. Explain.
Cu2+ has fewer electrons and a larger effective nuclear charge
Does atomic radius increase or decrease going across a row of the periodic table?
Decreases from left to Right
What does Eea stand for?
Electron Affinity
Describe periodic trends from electron affinity
Electron affinity increased across a row and decreases down a group
Put in order according to atomic radius
F < O < S
What is Coulomb's Law?
F= k x z1z2/d^2
Write as a compound: Iron (III) Sulfide
Fe2S3
What is the most electronegative element?
Flourine
What group is this describing? They have relatively lose Ei1, so they tend to lose their ns^1 valence-shell electron easily when they react, thereby adopting the electron configuration of the nobel gas in the previous row of the periodic table
Group 1A (Alkali-metal) elements
What group is this describing? They have relatively low Ei1 and Ei2, so they tend to lose both their ns^2 valence-shell electrons easily when they react and adopt a noble-gas electron configuration
Group 2A (Alkaline-earth) elements
What group is this describing? They have a relatively negative Eea, so they tend to gain one electron easily when they react, changing from ns^2 np^5 to ns^2 np^6 and thereby adopting the configuration of the neighboring noble gas in the same row
Group 7A (Halogen) elements
What group is this describing? They are essentially inert and undergo very few reactions. They neither gain not lose electrons easily.
Group 8A (noble-gas) elements
Draw an electron-dot structure for phosphine, PH3
H .. H:P:H ..
Propane, C3H8 , has a structure in which 3 carbon atoms are bonded in a row, each end carbon is bonded to three hydrogens, and the middle carbon is bonded to two hydrogens. Draw the structural formula.
H H H I I I H - C - C - C - H I I I H H H
Name all 7 diatomic molecules
H, N, O, F, Cl, Br, IDefin
Does H have a high or low electronegativity?
High
Does atomic radius increase or decrease going down a group of the periodic table?
Increases
Bonds between atoms whose electronegativity differ by more than about 2 units have what type of pole?
Ionic
What is NaCl's Polarity?
Ionic
What does Ei stand for?
Ionization Energy
Fe2O3
Iron (III) Oxide
Name Fe(CLO4)3
Iron (III) Perchlorate
Define ground-state electron configuration
It states that an atom or ion is a description of the atomic orbitals that are occupied in the lowest-energy state of the atom or ion.
Which has a larger radius? (Na or K); (V or Zn); (Li or Ba)
K ; V ; Ba
Why is the atomic radius higher going down a group?
Larger valence-shell orbitals are occupied
PbS
Lead (II) Sulfide
Put these atoms in order according to increasing atomic radius: K, Li, Na, Cs, Rb.
Li < Na < K < Rb < Cs
Name LiF
Lithium Fluoride
Name: LiNO3
Lithium nitrate
Define the Octet Rule
Main-group elements tend to undergo reaction that leave them with eight outer-shell electrons. That is, main-group elements react so that they attain a noble-gas electron configuration with filled s and p subshells in their valence electron shell
The amount of energy that must be added to remove an electron from a neutral atom to give a positive ion is called the atom's ionization energy. Which would you expect to have the larger ionization energy, Na or Mg? Explain.
Mg has a higher ionization energy than Na because Mg has a higher Zeff and a smaller size.
Write as a compound: Magnesium Floride
MgF2
Define Anions
Negative Ions
Do electrons in the same subshell shield?
No
Bonds between atoms with the same or similar electronegativity usually have what type of pole?
Nonpolar Covalent
What is Cl2's Polarity?
Nonpolar Covalent
Bonds between atoms whose electronegativity differ by less than 2 usually have what type of pole?
Polar Covalent
What is HCl's Polarity?
Polar Covalent
Define Cations
Positive Ions
Name KHSO4
Potassium Hydrogen Sulfate
Write as a compound: Tin (IV) Oxide
SnO2
Define Electronegativity
The ability of an atom in a molecule to attract the shared electrons in a covalent bond
Define Bond Dissociation Energy
The amount of energy released when a bond forms
Define electron affinity
The amount of energy released when an electron adds to a neutral atom to give a negative ion
Define ionization energy
The amount of energy that must be added to remove an electron from a neutral atom to give a positive ion
Define Lattice energy
The amount of energy that must be supplied to break an ionic solid into its individual gaseous ions and is thus a measure if the strength of the solid's ionic bonds.
Define Zeff
The effective nuclear charge is the net positive charge experienced by an electron in a multi-electron atom
Define Bond Length
The optimum distance between nuclei
Define Molecule
The unit of matter that results when two or more atoms are joined by covalent bonds
Where are elements likely to be more anion like?
Top right of the periodic table
Many early chemists noted a diagonal relationship among element in the periodic table, whereby a given element in sometimes more similar to the element below and to the right than it is to the element directly below. Lithium is more similar to Magnesium than to Sodium, for example, and Boron is more similar to Silicon than to Aluminum. Use your knowledge about the periodic trends of such properties as atomic radii and Zeff to explain the exsitance of diagonal relastionships
When moveing diagonally down and right on the periodic table, the increase in atomic radius caused by going to a larger shell is offset by a decrease caused by higher Zeff
What is the expected ground-state electron configuration of the recently discovered element with Z = 116?
[Rn]7s^2 5f^14 6d^10 7p^4
How many protons and electrons are in each of the following ions? a) Be^2+ b) Rb+ c) Se^2- d) Au^3+
a) 4p, 2e- b) 37p, 36e- c) 34p, 36e- d) 79p, 76e-
Name the following Ions : a) Ba^2+ b) Cs+ c) V^3+ d) HCO3- e) NH4+
a) Barium ion b) Cesium ion c) Vanadium (III) ion d) Hydrogen carbonate ion e) Ammonium ion
a) Which has the smaller second ionization energy, K or Ca? b) Which has the larger third ionization energy Ga or Ca?
a) Ca b) Ca
What are the formulas of the compounds formed from the following ions? a) Ca^2+ and Br- b) Ca^2+ and SO4^2- c) Al^3+ and So4^2-
a) CaBr2 b) CaSo4 c) Al2(SO4)3
Write formulas from compounds of calcium with each of the following a) Chlorine b) Oxygen c) Sulfer
a) CaCl2 b) CaO c) CaS
a) Which of the elements Be, N, O, and F has the most negative electron affinity? Explain. b) Which of the iron Se^2-, F-, O^2-, and Rb+ has the largest radius? Explain.
a) F b) Se^2-
Iron is commonly found as Fe, Fe^2+, and Fe^3+, a) write electron configurations for each of the three b) What are the n and l quantum numbers of the electrons removed on going from Fe^2+ to Fe^3+? c) The third ionization eergy of Fe is Ei3 = +2952 kJ/mol. What is the longest wavelength of light that could ionize Fe^2+(g) to Fe^3+(g)? d) The third ionization energy of Ru is less than the third ionization energy of Fe. Explain
a) Fe: [Ar] 4s^2 3d^6 ; Fe^2+: [Ar] 3d^6 ; Fe^3+: [Ar] 3d^5 b) n = 3 ; l = 2 c) 40.6nm d) The electron removed from Ru to go from Ru^2+ to Ru^3+ is a 4d electron. The electron with the higher principle quantum number, n = 4. is farther for the nucleus, less tightly held, and requires less energy to remove.
Write formula for the following binary compounds a) Potassium Chloride b) Tin (II) Bromide c) Calcium Oxide d) Barium Chloride e) Aluminum Hydride
a) KCl b) SnBr2 c) CaO d) BaCl2 e) AlH
What are the likely ground-state electron configurations of the following cations? a) La^3+ b) Ag+ c) Sn^2+
a) La^3+, [Xe] b) Ag+, [Kr] 4d^10 c) Sn^2+, [Kr] 5s^2 4d^10
Fill in the missing information to give formulas of the following compounds: a) Na?SO4 b) Ba?(Po4)? c) Ga?(SO4)?
a) Na2SO4 b) Ba3(PO4)2 c) Ga2(SO4)3
Give systematic names for the following compounds: a) PCl3 b) N2O3 c) P4O7 d) BrF5
a) Phosphorus Trichloride b) Dinitrogen Trioxide c) Tetraphosphorus Heptoxide d) Bromine Triflouride
Give the formulas and charges of the following ions: a) Sulfite ion b) Phosphate ion c) Zicronium (IV) ion
a) SO3^2- b) PO4^3- c) Zr^4+
Shared electrons are...
bonding pairs
What does the prefix hypo- mean?
less than
What does the prefix per- mean?
more than
What are charged, covalently bonded groups of atoms?
polyatomic ions
What are the subshells?
s, p, d, f
