MCAT Test Prep Chemistry Practice Passage

1. High first ionization energies and high first electron affinities are characteristic of which group of elements?

a. Halogens

b. Noble Gases

c. Alkali Earth Metals

d. Metalloids

Answer: High first ionization energies are associated with elements that hold onto their valance electrons extremely tightly. Of the answer choices, halogens are the best answer, choice A, because these elements need to gain one additional electron to achieve a noble gas configuration.

2. Which atom has the highest atomic radius?

a. Sulfur

b. Berylium

c. Oxygen

d. Calcium

Answer: When moving left to right across rows on the periodic table the atomic radius decreases as a result of there being an increase in the nuclear charge. Additionally, as you descend the atomic radius increase due to an increase in the number of shells holding electrons. Therefore, one would want to choose an element furthest to the left and lowest on the periodic table when looking for an element with the largest atomic radius. Making answer choice D the best answer.

3. Which of the following elements is considered a metalloid?

a. Oxygen

b. Fluorine

c. Neon

d. Silicon

Answer: Choice D is the best answer as Fluorine is considered a halogen, neon is considered a noble gas, and oxygen is considered a non-metal. Silicon is considered a metalloid.

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