CHEM 7-8

In which of the following molecules or ions does the central atom have an expanded octet? a) I3- b) N2O c) PCl3 d) AsF3 e) O3

a

Determine the wavelength of the line in the hydrogen atom spectrum corresponding to the n1= 3 to n2= 4 transition.

c) 1,875 nm

Which of the following compounds has a square pyramid geometry? a) SiF4 b) ICl3 c) PCl5 d) BrF5

d

In comparing the length and strength of single, double, and triple bonds between the same pair of atoms, the ________ a) shorter bond will be the weaker bond. b) longer bond can be either weaker or stronger than the other. c) longer bond will be the stronger bond. d) bond length and bond strength are not related. e) shorter bond will be the stronger bond.

e

Which of the following molecules is nonpolar? a) SF4 b) CHCl3 c) NH3 d) H2CO e) BF3 Question 46

e

The atomic radius of germanium (Z = 32) is smaller than the atomic radius of potassium (Z = 19) because of a) a decrease in the effective nuclear charge. b) an increase in the effective nuclear charge. c) a change in the n quantum number. d) germanium having 32 rather than 19 electrons. e) the fact that p and d orbitals have the same orbital penetration.

b

What is the orbital designation for an electron with the quantum numbers n= 3, l= 2? a) 3s b) 3d c) 2p d) 2f e) 3e

b

Which of the following molecules or ions has a linear molecular geometry? a) H2O b) ICl3 c) SO2 d) I3-

d

Which transition in a hydrogen atom requires the largest change in energy? a) n1= 9 to n2= 10 b) n1= 1 to n2= 2 c) n1= 2 to n2= 3 d) n1= 1 to n2= 3 e) n1= 2 to n2= 4

d

What is the formal charge of each atom (from left to right) in the following resonance structure of SN2?

-1,+1,0

How many valence electrons are in an ion, C6H5O73-? a) 48 b) 74 c) 68 d) 14 e) 71

b

If a metal has a work function of 3.43 x 10-19 J, calculate the longest wavelength of light that could be detected with a photoelectric detectors based on this metal?

a) 579 nm

The following Lewis symbol corresponds to which ion? (an X with 6 electrons) a) Si2- b) S- c) P2- d) Cl- e) Al3+

a) Si2-

Which of the transitions in the hydrogen atom energy-level diagram shown here requires the longest wavelength photon?

as n gets bigger, the wavelengths get longer

A ________ geometry corresponds to a steric number of ________. a) linear; 1 b) trigonal planar; 3 c) tetrahedral; 5 d) trigonal bipyramidal; 6 e) octahedral; 8

b

Given the balanced reaction and using the bond energies in the table below, estimate the enthalpy change associated with the reaction below. N2(g) + 3H2(g) → 2NH3(g) a) -860 kJ b) -82 kJ c) 988 kJ d) -605 kJ e) 212 kJ

b

If the principal quantum number is seven (n=7) and the angular momentum quantum number is three (l = 3), which of the following values is not an allowed value of the magnetic quantum number ( ml )? a) -3 b) 4 c) 2 d) 1 e) 0

b

What is the ground-state electron configuration for sulfur? a) 1s22s22p63s23p5 b) [Ne]3s23p4 c) 1s22s22p4 d) 1s22s22p5 e) [He]2s22p4

b

What type of bonding is present in NaNO3? a) ionic b) Ionic and polar covalent c) metallic d) nonpolar covalent e) polar covalent

b

Which of the following is not a possible set of quantum numbers for an electron? a) n= 3, l= 2,ml = -1 b) n= 2, l= 2,ml = 0 c) n= 4, l= 1,ml = 1 d) n= 1, l= 0,ml = 0 e) n= 2, l= 1,ml = 1

b

Which of the following objects, all moving at the same speed, will have the largest de Broglie wavelength? a) a proton b) an electron c) a neutron d) a bowling ball e) a neon atom

b

Which sequence has the elements arranged in order of increasing electronegativity? a) Cl < Br < I b) B < N < O c) H < Li < K d) C < N < H e) Al < Cl < S

b

Which subshell only has five orbitals? a) l = 1 b) l = 2 c) l = 3 d) l = 4 e) l = 5

b

What is the speed of an argon atom that has a de Broglie wavelength of 5.2 pm?

b) 1.9 × 103 m/s

In quantum mechanics, an atomic orbital ________ a) provides the position of an electron at any instant of time in the space around an atomic nucleus. b) is identical to the orbits Bohr used in his analysis of the hydrogen atom. c) provides the probability of finding an electron at any point in the space around an atomic nucleus. d) identifies the most probable position of an atomic nucleus. e) locates all the electrons in an atom.

c

What is the ground-state electron configuration of an Ni2+ ion? a) [Ar]3d84s2 b) [Ar]3d104s2 c) [Ar]3d8 d) [Ar]3d64s2 e) [Ar]3d10

c

Which one of the following statements about CH3CN is correct? (All the H atoms and N are terminal atoms.) a) It has one double bond. b) All atoms except N obey the octet rule in acetonitrile. c) It has one pair of nonbonding electrons. d) One carbon atom and the nitrogen atom have nonzero formal charges. e) It has 10 valence electrons.

c

Which statement below regarding formal charge is correct? a) Any negative formal charges should be on the least electronegative element. b) The formal charge of an atom in a molecule is the actual charge on that atom. c) The most stable (lowest energy) Lewis structure is the one with the most formal charges equal to zero or closest to zero. d) Formal charge on an atom in a bond is determined by the electronegativity of that atom.

c

Calculate the kinetic energy of the photoelectrons emitted from a metal surface (φ= 2.9 x 10-19 J) when it is irradiated by photons with a wavelength of 350 nm?

c) 2.8 x 10-19 J

Which of the following types of electromagnetic radiation have the longest wavelength? a) gamma rays b) X-rays c) radio waves d) blue light e) infra red

c) radio waves

How many orbitals are possible for the n = 2 shell? a) 1 b) 2 c) 3 d) 4 e) 5

d

How many resonance structures are there for SO3 when each atom satisfies the octet rule? a) 0 b) 1 c) 2 d) 3 e) 4

d

The correct H—N—H bond angle in NH3 is ________ a) the same as the H—O—H angle in water. b) exactly 109.5°. c) greater than 109.5°. d) less than 109.5°. e) 120°.

d

The electron configuration of a manganese ion (Z = 25) is [Ar]3d 3. What is the charge on this ion? a) +3 b) +2 c) +7 d) +4 e) +5

d

What l quantum numbers are possible when n= 3? a) 1 and 2 b) 1, 2, and 3 c) 0, 1, 2, and 3 d) 0, 1, and 2 e) any integer

d

What ml quantum numbers are possible when n= 2 and l= 1? a) 0 and 1 b) -2, -1, 0, 1, and 2 c) 0, 1 and 2 d) 0 e) -1, 0, and +1

e

Which of the following elements would you expect to have the greatest first ionization energy? a) B b) Be c) Li d) C e) O

e

Which of the following is most likely a polar covalent bond? a) H-H b) Na-Cl c) K-F d) Ca-O e) C-N

e

Which of the following statement(s) regarding quantum numbers that identify an atomic orbital are correct? a) The principal quantum number, n, identifies the size of an atomic orbital. b) The angular momentum quantum number, l , identifies the shape of an atomic orbital. c) The spin quantum number, ms, identifies the orientation of the orbital in space. d) The magnetic quantum number, ml , can have values that range from -l to +l in integer steps. e) All statements are correct.

e

Which statement best summarizes the Heisenberg uncertainty principle? a) The position and energy of an electron in an atom cannot both be precisely known. b) The mass and velocity of an electron in an atom cannot both be precisely known. c) The mass and position of an electron in an atom cannot both be precisely known. d) The mass and momentum of an electron in an atom cannot both be precisely known. e) The position and momentum of an electron in an atom cannot both be precisely known.

e

What is the frequency (ν, in Hz) of the photons emitted by an He-Ne laser with a wavelength (λ) of 552.8 nm?

e) 5.423 x 1014

Choose the highest energy photons. a) Frequency of radiation is 6.0 x 1010 b) Frequency of radiation is 1.750 GHz c) Frequency of radiation is 106.7 MHz d) Wavelength of radiation is 650 nm e) Wavelength of radiation is 100 pm

e) Wavelength of radiation is 100 pm