SAT II Chemistry : SAT Subject Test in Chemistry

Study concepts, example questions & explanations for SAT II Chemistry

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Example Questions

Example Question #1 : The Periodic Table

The following is a modified true/false question. In it, you must decide if each individual statement is true (T) or false (F). If both are true, then you must also decide if the second statement is a correct explanation (CE) of the first statement.

I: Atoms in the alkaline earth metal group have smaller ionic radii than their atomic radii

BECAUSE

II: atoms in this group usually lose electrons in order to become ions, resulting in the ion lacking the outermost energy level present in the atom.

Possible Answers:

T, F

F, T

T, T (II is not a correct explanation of I)

F, F

T, T, CE

Correct answer:

T, T, CE

Explanation:

The alkaline earth metals are the elements in group II, such as beryllium and magnesium. They want to have a complete octet in their outermost energy level, so they tend to lose two electrons to form the ionic state, which gives them the electron configuration of the noble gas in the previous energy level and thus a smaller ionic radius. Therefore, both statements are true and the second correctly explains the first.

Example Question #1 : Sat Subject Test In Chemistry

The elements with the smallest atomic radii tend to be found in which part of the periodic table?

Possible Answers:

The bottom left corner

The inner transition metals

The bottom right corner

The upper right corner

The upper left corner

Correct answer:

The upper right corner

Explanation:

Atomic radius tends to increase down a group due to the addition of new energy levels; however, it decreases across a period due to increased shielding and increased nuclear mass. For these reasons, the elements with the smallest atomic radii would be in the upper right corner of the periodic table.

Example Question #2 : Sat Subject Test In Chemistry

An atom of phosphorus has 15 protons, 16 neutrons, and 15 electrons. What is the atom's mass number?

Possible Answers:

Correct answer:

Explanation:

Protons and neutrons both have masses of approximately 1 amu, whereas the mass of an electron is negligible. Therefore, the mass number is equal to the number of protons and neutrons, which is 31.

Example Question #3 : Sat Subject Test In Chemistry

Which of the following has the electron configuration of ?

Possible Answers:

Correct answer:

Explanation:

The task is to find the atom or ion with its first three energy levels completely filled. Argon is not an answer choice, which means that it must be one of the ions with an atomic number close to argon's atomic number. Recalling that a positive charge means electrons were lost from the outermost shell and that a negative charge means electrons were gained in the outermost shell, the only answer that works is .

Example Question #1 : Electrons And Quantum Theory

Which of the following variables identifies the sublevel that has three orbitals?

Possible Answers:

Correct answer:

Explanation:

The  sublevel contains three orbitals, whereas the other levels listed contain different numbers of orbitals. The  level has one orbital; the  level has five; the  level has seven; and there is no  sublevel.

Example Question #1 : Molecules

Based on VSEPR theory and electron configurations, which of the following molecules is not matched with its correct geometry?

Possible Answers:

 - Trigonal planar

 - Tetrahedral

 - Linear

 - Bent (v-shaped)

 - Linear

Correct answer:

 - Trigonal planar

Explanation:

 has three bonding pairs and one non-bonding pair, which is the geometry for trigonal pyramidal, not trigonal planar.

Example Question #2 : Molecules

What is the molecular geometry of ?

Possible Answers:

Square pyramidal

Octahedral 

Trigonal pyramidal 

Tetrahedral 

Square planar 

Correct answer:

Square pyramidal

Explanation:

There are six electron domains in  has five bonding and one nonbonding pairs of electrons. The electron domain geometry of  is octahedral. When a molecule has octahedral electron domain geometry and has five bonding and one nonbonding pairs, the molecular geometry is square pyramidal.

Example Question #1 : Compounds

Which of the following is the correct name of ?

Possible Answers:

Nitrogen monoxide

Nitrogen dioxide

Dinitrogen monoxide

Dinitrogen tetraoxide

Dinitrogen pentoxide 

Correct answer:

Dinitrogen tetraoxide

Explanation:

In order to answer the question, it is important to first determine what kind of bonding is occurring in order to properly name the molecule. When nitrogen and oxygen form an  molecule, electrons are shared between the atoms, so a covalent bond is formed.

Because a covalent bond is formed, we can determine that name of the molecule will be based on number of each atom in the molecule. There are two nitrogen atoms in the resulting molecule, so the prefix in front of the "nitrogen" part of the name will be "di-," meaning two. There are four oxygen atoms in the resulting molecule, so the prefix in front of the "oxygen" part of the name will be "tetra," meaning four.

The molecules names will be arranged alphabetically, and the second atom will have "-ide" as the suffix. Therefore, the correct answer is "dinitrogen tetroxide."

Example Question #7 : Sat Subject Test In Chemistry

What is the formula for the compound formed from calcium and sulfate ions?

Possible Answers:

Correct answer:

Explanation:

In order to answer this question correctly, it is important to have knowledge of the formation of ionic bonds, polyatomic ions, and the periodic table. First, it is important to notice that calcium ions and sulfate ions will form an ionic bond. Knowing this, it can be understood that valance electrons will be exchanged between the ions and therefore, oppositely charged ions that are attracted to each other will be formed.

Calcium is in the second column of the periodic table, so it will provide two ions to the sulfate polyatomic ion. This will form a calcium cation () and a sulfate polyatomic anion ().

One calcium ion provides two electrons, which are both accepted by a sulfate polyatomic ion, so the ratio of calcium ions used to sulfate polyatomic ions used is 1:1. This means that only one of each ion is needed to form the compound, making the formula .

Initially it may be tempting to write the formula as ; however, since both ions have a "2" subscript in this form, it is redundant to the formula in this way. Only one of each ion is needed to form the compound.

Example Question #2 : Compounds

All of the following are properties of zinc. Which of the following are chemical properties of zinc?

A. Zinc produces hydrogen gas when placed in acid.

B. Zinc melts at .

C. The density of zinc is .

D. Zinc is a grey metal.

E. Zinc corrodes in moist air.

Possible Answers:

A, C, and E 

 A and E

B and C

C

B

Correct answer:

 A and E

Explanation:

Physical properties are aspects of matter that can be observed and measured without changing it. Chemical properties measure the potential for undergoing a chemical change. How zinc reacts to acid and in moist air are both chemical properties because the zinc is undergoing chemical change in each environment. The color, density, and melting point of the zinc can all be observed without changing the nature of the matter, so these are physical properties of zinc.

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