Chemistry Exam IV Practice Problems

Flashcards based on practice problems from the Chemistry Exam IV covering topics including atomic structure, periodic trends, molecular geometry, and gas laws.

In which set of elements would all members be expected to have very similar chemical properties?

A) O, S, Se

Atomic radius generally increases as we move _

B) down a group and from right to left across a period

What is the correct order for atomic radius for Mg, P, Si and Ar?

E) Na > Mg > Si > P > Ar

Which isoelectronic series is correctly arranged in order of increasing radius?

D) Ca²⁺ < K⁺ < Ar < Cl⁻

Order of first ionization energies?

B) Ar > Cl > S > Si > Al

The effective nuclear charge of an atom is primarily affected by _.

C) inner electrons

Which ion has the largest radius?

B) Br⁻

Of the following elements, _ has the most negative electron affinity.

E) Cl

Sodium is much more apt to exist as a cation than is chlorine. This is because _.

D) chlorine has a greater ionization energy than sodium does

The list that correctly indicates the order of metallic character is _.

E) Si > P > S

Reacting CO₂ with water results in a(n) solution.

B) acidic

Which metals differ in the number of d-electrons?

A) Fe and Cu

Nonmetals can be _ at room temperature.

D) solid, liquid, or gas

Hydrogen is unique among the elements because _.

B) Its electron is not at all shielded from the nucleus.

Alkali metals tend to be more reactive than alkaline earth metals because _.

C) alkali metals have lower ionization energies

Which statements are true about the general valence electron configuration of ns² np⁵?

C) (i), (iii), (iv)

_ is isoelectronic with helium.

D) H⁻

Which of the following elements can exist as an allotrope?

C) Carbon

The electron configuration belonging to the atom with the highest second ionization energy is:

E) (v) 1s² 2s² 2p⁶ 3s² 3p⁵

The electron configuration of the atom with the most negative electron affinity is:

E) (v) 1s² 2s² 2p⁶ 3s² 3p⁵

Lattice energy is _.

D) the energy required to convert a mole of ionic solid into its constituent ions in the gas phase

In ionic bond formation, the lattice energy of ions as the magnitude of the ion charges and the radii .

D) increases, increase, decrease

The type of compound that is most likely to contain a covalent bond is _.

A) one that is composed of only nonmetals

Of the molecules below, the bond in _ is the most polar.

B) HF

How many electrons are in the Lewis structure of a nitrite ion (NO₂⁻)?

D) 18

Resonance structures differ by _.

B) placement of electrons only

For forms of a molecule or ion, the observed structure is an average of the forms.

C) resonance, resonance

A valid Lewis structure of _ cannot be drawn without violating the octet rule.

E) IF₃

Of the bonds C–C, C=C, C≡C, the C–C bond is _.

E) weakest/longest

Based on the octet rule, phosphorus most likely forms a _ ion.

E) P³⁻

The basis of the VSEPR model of molecular bonding is _.

A) electron domains in the valence shell of an atom will arrange themselves so as to minimize repulsions

Of the following species, _ will have bond angles of 120°.

C) BCl₃

The central Xe atom in the XeF₄ molecule has unbonded electron pair(s) and bonded electron pair(s) in its valence shell.

E) 2, 4

An electron domain consists of _.

E) a, b, and c

What is the molecular shape of H₂O?

B) bent

The molecular geometry consists of _.

D) b and c

Of the molecules below, only _ is nonpolar.

C) BF₃

Three monosulfur fluorides are observed: SF₂, SF₄, and SF₆. Of these, _ is/are polar.

A) SF₂ and SF₄ only

Of the following molecules, only _ is polar.

A) NCl₃

The combination of two atomic orbitals results in the formation of _ molecular orbitals.

B) 2

The sp² atomic hybrid orbital set accommodates _ electron domains.

B) 3

The hybridization of nitrogen in NF₃ and NH₃ are and , respectively.

C) sp³, sp³

A typical double bond _.

E) All of the above answers are correct

The pi bond in ethylene (H₂C=CH₂) results from the overlap of _.

C) p atomic orbitals

The hybridization of nitrogen in the H–C≡N molecule is _.

C) sp

Electrons in bonds remain localized between two atoms. Electrons in bonds can become delocalized between more than two atoms.

A) sigma, pi

In comparing the same two atoms bonded together, the the bond order, the the bond length, and the _ the bond energy.

A) greater, shorter, greater

Based on molecular orbital theory, the bond order of the H–H bond in the H₂⁺ ion is .

E) 1/2

According to the MO theory, overlap of two s atomic orbitals produces _.

B) one bonding molecular orbital and one antibonding molecular orbital

A molecular orbital can accommodate a maximum of _ electron(s).

B) 2

Gaseous mixtures _.

C) are all homogeneous

Which of the following is not a unit of pressure?

E) mm

Which statement about atmospheric pressure is false?

D) With an increase in altitude, atmospheric pressure increases as well.

Standard temperature and pressure (STP), in the context of gases, refers to _.

E) 273.15 K and 1 atm

After compression, the gas pressure was _ atm.

C) 16.0

The new volume of the gas is _ L.

A) 3.1

A 0.325 L flask filled with gas at 0.851 atm and 19°C contains _ mole of gas.

D) 0.0116

The density of HCN is _ g/L at STP.

E) 0.829

The thermal decomposition of potassium chlorate can be used to produce oxygen in the laboratory.

A) 3.7

Which of the following is not part of the kinetic-molecular theory?

D) Atoms are neither created nor destroyed by ordinary chemical reactions.