Review Questions for Exam 3 - Chem 101
Which of the following corresponds to an electron configuration of a carbon atom in an excited state?
1s²2s²2p¹3s¹
How many unpaired electrons does the element cobalt (Co) have in its lowest energy state?
3
Ideal gas molecules are best considered to be
non-polar
In general, the rows on the periodic table correspond to ______________ and the columns numbered 1A, 2A, ... 8A correspond to ______________ .
the energy level of the valence electrons; the number of valence electrons
In an exothermic reaction...
the products are more stable than the reactants
Which of the following is a linear molecule in which the central atom has three lone electron pairs?
KrF₂
Consider the carbon monoxide molecule pictured below. Note that the bond may be a single, double or triple bond. What can best be said about the electrons involved in the bond?
A bonding electron is more likely to exist in the area marked by Box B because the oxygen nucleus has a stronger attraction for electrons than does the carbon nucleus
Which of the following one electron species has the highest ionization energy?
Be³⁺
Which of the following has the lowest boiling point?
CH₄
Rank the following from smallest to largest atomic radius: S²⁻, Ca²⁺, K⁺, Cl⁻.
Ca²⁺ < K⁺ < Cl⁻ < S²⁻
Which of the following requires the least energy to remove an electron?
Ca⁺
How many electrons can be contained in all of the orbitals with a principle energy level of 3?
18
Which electron is in the lowest energy state?
An electron in the 1s orbital of the uranium (U) atom
All molecules with polar bonds are thus polar overall.
False. Even though a molecule may contain polar bonds between atoms, the molecule could be nonpolar overall because the individual dipoles could "cancel," resulting in an overall net dipole moment of zero. One example of this is CH₄.
Methane (CH₄) is more likely to form stronger hydrogen bonding interactions than water (H₂O).
False. Hydrogen bonding does not exist between methane molecules. Hydrogen bonding interactions only occur when hydrogen is directly attached to an oxygen, nitrogen, or fluorine atom within the molecule.
Molecules that only exhibit London dispersion forces are always found in the gaseous state at room temperature.
False. Molecules that only exhibit London dispersion forces can be found in all three states. The more electrons a molecule contains, the stronger the London dispersion forces become between those molecules, resulting in a solid or liquid in some cases.
Which of the following ranks the compounds from smallest to largest bond angle around the central atom?
NH₃, BF₃, CO₂
Which of the following processes releases energy?
None of the above processes (a-c) release energy.
Rank the following from smallest to largest atomic radius.
O, Zn, Ca, Ba
To remove one electron from Mg requires a certain amount of energy. Which of the following is the best statement concerning the amount of energy in removing a second electron from magnesium?
Removing the second electron requires more energy because the second electron is being taken from a positive ion.
IF₃ Shape? Bond angle? Polarity?
Shape: T-shape Bond angle: 90°, 180° Polarity: polar
CF₃Cl Shape? Bond angle? Polarity?
Shape: tetrahedral Bond angle: 109° Polarity: polar
NO₃⁻ Shape? Bond angle? Polarity?
Shape: trigonal planar Bond angle: 120° Polarity: non-polar
SO₃²⁻ Shape? Bond angle? Polarity?
Shape: trigonal pyramid Bond angle:107° Polarity: polar
Which of the following best describes BF₃ and NF₃? (Note: Geometry refers to the electron pair arrangement and shape refers to the atom arrangement.)
They have different geometries and different shapes.
The electron configuration 1s²2s²2p⁶3s²3p⁶ is the correct electron configuration for the most stable form of which ion?
The calcium ion
Consider the following representation of a 2p-orbital: (look at pic in book) Which of the following statements best describes the movement of electrons in a p-orbital?
The electron movement cannot be exactly determined.
