Test 1 practice test MCQ Flashcards by Andrea Pedraza-Heakin

(quantum Theory)
Quantum theory primarily describes the behavior of:
a) Macroscopic objects
b) Subatomic particles
c) Planets and celestial bodies
d) Chemical reactions

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(Quantum Theory)
In classical physics, particles have:
a) Fixed positions and velocities
b) Probabilistic positions and velocities
c) No defined motion
d) Random behavior

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(Quantum Theory)
Which of the following is not a key principle of quantum mechanics?
a) The quantization of energy
b) The uncertainty principle
c) The conservation of mass
d) Wave-particle duality

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(Radial Probability Distribution)
The radial probability distribution describes the likelihood of finding an electron at a given:
a) Speed
b) Distance from the nucleus
c) Temperature
d) Charge state

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(Radial Probability Distribution)
As the principal quantum number (n) increases, the radial probability distribution:
a) Becomes more compact and shifts toward the nucleus
b) Remains unchanged
c) Becomes more spread out and shifts further from the nucleus
d) Becomes unpredictable

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(Wave Mechanics in Hydrogen)
The Schrödinger equation describes:
a) The motion of planets
b) The wave nature of electrons in atoms
c) Chemical bonding only
d) The behavior of gases under pressure

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(Wave Mechanics in Hydrogen)
In a hydrogen atom, the energy of an electron is given by:
a) E= mc^2
b)En= -13.6eV/n^2
c) F=ma
d) pV=nRT

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(Wave Mechanics in Hydrogen)
As the principal quantum number
𝑛
n increases, the energy:
a) Becomes more negative and the orbital radius shrinks
b) Becomes less negative and the orbital radius expands
c) Remains unchanged
d) Increases without limit

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(Quantum Numbers & Orbital Properties)
The principal quantum number
𝑛
n determines:
a) The size and energy of the orbital
b) The shape of the orbital
c) The orientation of the orbital
d) The spin of the electron

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(Quantum Numbers & Orbital Properties)
When the angular momentum quantum number
𝑙
l is 2, the orbital type is:
a) s
b) p
c) d
d) f

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The spin quantum number
𝑚𝑠
can have values of:
a) Any real number
b) +1 and -1
c) +1/2 and -1/2
d) 0 and 1

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(Multi-Electron Atoms)
In multi-electron atoms, energy levels are more complex due to:
a) The presence of protons
b) The interaction between electrons
c) The motion of neutrons
d) The influence of gravity

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(Multi-Electron Atoms)
In multi-electron atoms, why do 4s orbitals fill before 3d orbitals?
a) 4s orbitals have higher energy than 3d orbitals
b) 4s orbitals have lower energy than 3d orbitals initially
c) The filling order is random
d) Electron spin forces them into 4s first

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What does the electron configuration of an atom determine?
a) Its mass
b) Its atomic number
c) Its chemical properties
d) Its color

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Electron configuration notation is typically written in the form of:
a) Ionic charges
b) Orbital diagrams
c) Electron clouds
d) Electron distribution in atomic orbitals

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According to the Aufbau principle, electrons will occupy orbitals based on:
a) Atomic mass
b) Orbital shape
c) The energy of the orbitals
d) The color of the atom

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Which rule states that electrons fill degenerate orbitals singly before pairing up?
a) Pauli Exclusion Principle
b) Aufbau Principle
c) Hund’s Rule
d) Heisenberg Principle

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What does the penetration effect describe?
a) How electrons affect atomic mass
b) How electrons are repelled by the nucleus
c) How closely an electron can approach the nucleus
d) How much space an orbital takes up

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Which element’s electron configuration anomaly is due to a half-filled d-subshell being more stable than a partially filled one?
a) Sodium
b) Chromium
c) Neon
d) Chlorine

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When a sodium atom forms a Na⁺ ion, it loses one electron. What is the electron configuration of Na⁺?
a) Same as Ne
b) Same as Ar
c) Same as Cl
d) Same as Na

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Which of the following is true about ionization energy?
a) It increases down a group
b) It increases across a period
c) It is independent of atomic size
d) It decreases across a period

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What trend is observed in atomic size as you move across a period?
a) Increases
b) Decreases
c) Remains the same
d) Becomes erratic

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Which of the following is true about electronegativity across a period?
a) It decreases
b) It increases
c) It remains constant
d) It is unaffected by nuclear charge

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Which of the following best describes the primary difference between ionic and covalent bonds?
a. Ionic bonds form between two nonmetals, and covalent bonds form between a metal and a nonmetal.
b. Ionic bonds involve the sharing of electrons, while covalent bonds involve the transfer of electrons.
c. Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.
d. Ionic bonds form in gases, and covalent bonds form in solids.

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What is the main factor that determines the strength of an ionic bond? a. The type of atoms involved. b. The size and charge of the ions. c. The type of orbital overlap. d. The distance between atoms.

Which of the following statements is true about covalent bonds? a. Electrons are transferred between atoms. b. They generally form between a metal and a nonmetal. c. Electrons are shared between atoms with similar electronegativities. d. They result in the formation of ions.

In which scenario will an ionic bond most likely form? a. Between two nonmetals. b. Between two metals. c. Between a metal and a nonmetal. d. Between two atoms with the same electronegativity.

Which bond type typically results in a higher boiling point? a. Ionic bonds. b. Covalent bonds. c. Metallic bonds. d. Hydrogen bonds.

Which of the following pairs of atoms would form the most polar covalent bond? a. O—H b. H—H c. F—H d. C—H

Which factor primarily affects the strength of ionic bonds? a. The number of valence electrons. b. The temperature of the substance. c. The size and charge of the ions. d. The type of orbitals involved.

What is the primary purpose of Lewis structures? A) To represent the molecular geometry of compounds. B) To depict the bonding between atoms and the lone pairs of electrons. C) To calculate the molecular mass of compounds. D) To determine the polarity of molecules.

According to VSEPR theory, how do electron pairs around a central atom arrange themselves? A) To maximize repulsion and minimize attraction. B) To minimize repulsion and maximize attraction. C) To minimize repulsion and maximize repulsion. D) To maximize repulsion and minimize repulsion.

Which of the following electron geometries corresponds to 4 electron pairs around a central atom? A) Linear B) Trigonal Planar C) Tetrahedral D) Trigonal Bipyramidal

In the molecular geometry of a molecule with 3 bonding pairs and 1 lone pair, what is the shape? A) Trigonal Planar B) Tetrahedral C) Trigonal Pyramidal D) Bent

Which of the following molecules has a trigonal planar electron geometry? A) CO₂ B) BF₃ C) CH₄ D) PF₅

What is the bond angle in a molecule with a tetrahedral electron geometry? A) 90° B) 120° C) 109.5° D) 180°

Which of the following molecules has a bent molecular geometry? A) CO₂ B) H₂O C) NH₃ D) CH₄

What is the effect of lone pairs on bond angles in a molecule? A) They increase bond angles. B) They decrease bond angles. C) They have no effect on bond angles. D) They cause bond angles to become 90°.

Which of the following molecules has a linear molecular geometry? A) CO₂ B) H₂O C) NH₃ D) CH₄

What determines the polarity of a molecule? A) The number of bonds in the molecule. B) The electronegativity difference between atoms and the molecular geometry. C) The number of lone pairs on the central atom. D) The number of atoms in the molecule.

Which of the following molecules is nonpolar? A) H₂O B) CO₂ C) NH₃ D) CH₄

What is the primary focus of Valence Bond Theory (VBT)? A) Electron cloud distribution B) The overlap of atomic orbitals C) The repulsion of electron pairs D) The sharing of electron pairs

Which type of bond is formed by the side-by-side overlap of two p-orbitals? A) Sigma bond B) Pi bond C) Hydrogen bond D) Ionic bond

What is the shape of a molecule with sp hybridization? A) Linear B) Trigonal planar C) Tetrahedral D) Octahedral

Which hybridization involves one s orbital and three p orbitals? A) sp² B) sp C) sp³ D) sp³d

Which of the following is true about sigma bonds compared to pi bonds? A) Sigma bonds are always weaker than pi bonds. B) Sigma bonds occur along the bond axis and are generally stronger. C) Pi bonds form along the bond axis and are stronger. D) Pi bonds occur along the bond axis and are weaker.

Which molecule undergoes sp² hybridization? A) CO₂ B) CH₄ C) Ethene (C₂H₄) D) NH₃

In a triple bond, how many pi bonds are present? A) One B) Two C) Three D) None

What is the molecular geometry of a molecule with sp³ hybridization? A) Linear B) Tetrahedral C) Trigonal planar D) Octahedral

Which of the following is a limitation of Valence Bond Theory? A) It explains delocalized electrons well. B) It doesn't explain paramagnetism in molecules. C) It is useful for complex metal bonding. D) It does not account for electron repulsion.

In MO Theory, molecular orbitals are formed by combining atomic orbitals through which method? A) Geometric combination B) Linear combination C) Exponential combination D) Quadratic combination

When atomic orbitals combine constructively, they form a molecular orbital that is: A) Higher in energy than the original atomic orbitals B) Lower in energy than the original atomic orbitals C) Equal in energy to the original atomic orbitals D) Unchanged in energy

The principle stating that the number of molecular orbitals formed equals the number of atomic orbitals that combine is called the: A) Pauli Exclusion Principle B) Hund's Rule C) Aufbau Principle D) Conservation Principle

In diatomic molecules with an atomic number less than 8, which molecular orbital is higher in energy? A) σ2p B) π2p C) σ1s D) π1s

According to MO Theory, if a molecule has a bond order of zero, the molecule is: A) Stable B) Unstable

In MO Theory, when atomic orbitals combine constructively, they form a ________ molecular orbital, which is ________ in energy than the original atomic orbitals. a) bonding; higher b) antibonding; higher c) bonding; lower d) antibonding; lower

In diatomic molecules like O₂ and N₂, the p-orbitals combine to form: a) only σ molecular orbitals b) only π molecular orbitals c) both σ and π molecular orbitals d) neither σ nor π molecular orbitals

The Highest Occupied Molecular Orbital (HOMO) is: a) the lowest energy molecular orbital that contains electrons b) the highest energy molecular orbital that contains electrons c) the lowest energy molecular orbital that is empty d) the highest energy molecular orbital that is empty

In solids, the energy difference between the valence band and the conduction band is called the: a) HOMO-LUMO gap b) Band gap c) Energy gap d) Conduction gap

Materials with a large band gap that prevents electrons from moving to the conduction band are classified as: a) Conductors b) Semiconductors c) Insulators d) Metals

According to MO Theory, if a molecule has unpaired electrons in its molecular orbitals, it is classified as: a) Diamagnetic b) Paramagnetic c) Ferromagnetic d) Non-magnetic

Which of the following conditions must be met for a molecular vibration to be IR-active? A) The vibration must involve a change in the molecule's polarizability. B) The vibration must involve a change in the molecule's dipole moment. C) The vibration must involve a change in the molecule's mass. D) The vibration must involve a change in the molecule's bond length.

Which of the following molecules would exhibit IR-inactive stretching vibrations? A) HCl B) CO C) N₂ D) H₂O

For a nonlinear polyatomic molecule with 5 atoms, how many fundamental vibrational modes are expected? A) 6 B) 7 C) 9 D) 12

Which type of vibrational mode involves the movement of atoms in opposite directions within the same plane, similar to the motion of a pair of scissors? A) Rocking B) Wagging C) Scissoring D) Twisting

In the context of molecular vibrations, degeneracy refers to: A) Vibrational modes that involve bending motions. B) Vibrational modes that involve stretching motions. C) Multiple vibrational modes having the same energy. D) Vibrational modes that are IR-inactive.

Which of the following statements is not true? A.)The atomic radius decreases from left to right through a period of elements. B.)The atomic radius increases down the periodic table. C.)Cations are larger than the atoms from which they are formed. D.)The ionization energy increases from left to right through a period of elements.

Which statement about periodic trends is correct? A.)In most cases, energy is released when the first electron is added to an isolated gaseous atom. B.)Metallic character decreases down a group. C.)Most metals tend to form acidic oxides. D.)Anions are smaller than the corresponding neutral atoms

The following set of quantum numbers is not allowed: n = 3, l =0, ml = −2. Assuming that the n and ml values are correct, change the l value to an allowable combination. A.)l = 2 B.)l = 4 C.)l = 1 D.)l = 3

Lewis dot symbols represent the… A.)number of highest energy electrons. B.)total number of electrons. C.)group number for all elements. D.)number of highest energy protons.

A molecular orbital is… A.)a wave function that describes the individual bonds. B.)a Lewis structure picture model focusing on individual atomic bonds. C.)another description for valence bond hybrid orbitals. D.)a wave function describing the behavior of electrons in a molecule.