1. If a representative element is in group VA of the periodic table, how many el
ID: 907678 • Letter: 1
Question
1. If a representative element is in group VA of the periodic table, how many electrons are there in the valence shell of that element?
A. five electrons
B. three electrons
C. eight electrons
D. It cannot be determined from the information given because of Heisenberg's uncertainty principle.
E. It cannot be determined from the information given because the number of valence electrons must be determined by drawing a Bohr model of the element in question.
2. As an electron drops from the n=5 level to the n=2 level,
A. light of one color is emitted.
B. light of various colors is emitted.
C. light is absorbed.
D. heat is absorbed.
E. heat is released.
3. A sulfur atom would form its most stable configuration by
A. gaining two electrons.
B. gaining one electron.
C. losing one electron.
D. losing two electrons.
E. not gaining nor losing electrons.
4. Valence shell electron pair repulsion (VSEPR) theory is based on which of the following concepts?
A. The concept that electrons in a molecule will repel each other due to their negative charge.
B. The concept that valence electrons repel each other due to their small size.
C. The concept that valence electrons are attracted to protons found in the nucleus of the atom, since electrons are negatively charged while protons carry a positive charge.
D. The concept that electrons are very large particles and occupy a large amount of space inside a molecule.
E. The concept that valence electrons are attracted to the nucleus of an atom and therefore will spread as little as possible from each other.
5. Hydrogen bonding occurs whenever hydrogen is directly bonded to a small highly electronegative atom. Select the elements that may be involved in hydrogen bonding. C, N, O, F, Si, Cl
A. N and O
B. C and N
C. Si and F
D. F and Cl
E. O and C
6. What is the strongest intermolecular force of attraction holding together network solids, such as diamond and quartz sand?
A. covalent bonds
B. London forces
C. dipolar forces
D. hydrogen bonds
E. ionic bonds.
7. Choose the best description for a solid held together by London forces.
A. This substance melts at -30 °C to give a liquid that does not conduct electricity.
B. This substance melts at 650 °C and both the solid and liquid phases conduct electricity.
C. This substance melts at 390 °C to give a liquid that conducts electricity.
D. This substance melts at 1100 °C to give a liquid that does not conduct electricity.
E. This substance melts at 850 °C. The solid does not conduct electricity while the liquid does.
8. In a chemical reaction, dynamic equilibrium occurs when the rate of the forward reaction becomes precisely equal to the rate of the reverse reaction. All of the following statements are true EXCEPT
A. A dynamic equilibrium occurs when the reaction is more than 50 percent complete.
B. In a dynamic equilibrium, reactants are converted to products at the same rate as products become reactants.
C. Reactions that reach a dynamic equilibrium are often referred to as reversible reactions.
D. Reactions that reach a dynamic equilibrium are shown with a double arrow, to indicate the forward and reverse reactions.
E. Reactions that reach equilibrium very close to the end (product side) are usually shown with only one arrow instead of a double arrow and we say the reaction goes to completion.
9. Le Chatelier's principle states that if a reaction at equilibrium is disturbed, the reaction will return to equilibrium by shifting in such a direction as to partially undo the disturbance. The following are examples of methods used in disturbing the equilibrium EXCEPT
A. Adding more of one reactant to change the concentration of that reactant.
B. Removing product molecules, thereby decreasing the concentration of products.
C. Adding a small amount of substance that does not react with any of the reactants or products.
D. Increasing the temperature if the reaction is exothermic.
E. Increasing the temperature if the reaction is endothermic.
10. A radioactive isotope may change a proton into a neutron in an attempt to become more stable. While doing so, a particle is emitted from the nucleus of that isotope. This conversion can occur via two different processes. Select the choices that show these conversions.
A. 3 and 5
B. 4 and 5
C. 1 and 4
D. 2 and 4
E. 2 and 3
Explanation / Answer
1)A
2)A
3)A
4)A
5)D
6)A
7)A
8)B
9)D
10)
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