AP Chem diagnostic test

Which of the following statements about the periodic table and atomic structure is correct?

• Elements in the same period have similar chemical properties because they have the same number of valence electrons.

• The atomic radius generally decreases from left to right across a period due to increasing nuclear charge.

• The first ionization energy of elements decreases as you move down a group because the outermost electrons are closer to the nucleus.

• Isotopes of an element have different numbers of protons and thus different chemical properties.

How does increasing the temperature generally affect the rate of a chemical reaction?

• It decreases the reaction rate because the reactants have lower kinetic energy.

• It has no effect on the reaction rate.

• It increases the reaction rate by providing more kinetic energy to the reactants, leading to more frequent and energetic collisions.

• It decreases the reaction rate by decreasing the frequency of collisions between reactants.

Based in the reaction, which substance is being oxidized?

• Zinc

• Hydrogen

• Chlorine

• None

Which of the following correctly describes a characteristic of a strong acid?

• It partially dissociates in water, producing few hydrogen ions.

• It completely dissociates in water, producing a high concentration of hydrogen ions.

• It has a pH close to 7 in aqueous solutions.

• It produces hydroxide ions in solution.

pH level of pure water:

When 4.0 moles of aluminum react with excess chlorine gas, how many moles of aluminum chloride are produced?

• 2.0

• 4.0

• 6.0

• 8.0

Which of the following statements best describes the atomic radius trend in the periodic table?

• Atomic radius decreases from left to right across a period and increases from top to bottom in a group.

• Atomic radius decreases from left to right across a period and decreases from top to bottom in a group.

• Atomic radius increases from left to right across a period and increases from top to bottom in a group.

• Atomic radius increases from left to right across a period and decreases from top to bottom in a group.

Which type of bond is characterized by the sharing of electrons between two nonmetal atoms?

Which molecule has the strongest bond?

• H₂

• Cl₂

• O₂

• N₂

In an exothermic reaction, which of the following is true about the enthalpy change (ΔH)?

• ΔH is positive

• ΔH is negative

• ΔH is zero

• ΔH depends on the temperature