SAT Subject Test Chemistry

PART 2

REVIEW OF MAJOR TOPICS

CHAPTER 2

Atomic Structure and the Periodic Table of the Elements

Practice Exercises

1. The two main regions of an atom are the

(A) principal energy levels and energy sublevels

(B) nucleus and kernel

(C) nucleus and energy levels

(D) planetary electrons and energy levels

2. The lowest principal quantum number that an electron can have is

(A) 0

(B) 1

(C) 2

(D) 3

3. The sublevel that has only one orbital is identified by the letter

(A) s

(B) p

(C) d

(D) f

4. The sublevel that can be occupied by a maximum of 10 electrons is identified by the letter

(A) d

(B) f

(C) p

(D) s

5. An orbital may never be occupied by

(A) 1 electron

(B) 2 electrons

(C) 3 electrons

(D) 0 electrons

6. An atom of beryllium consists of 4 protons, 5 neutrons, and 4 electrons. The mass number of this atom is

(A) 13

(B) 9

(C) 8

(D) 5

7. The number of orbitals in the second principal energy level, n = 2, of an atom is

(A) 1

(B) 9

(C) 16

(D) 4

8. Lewis structure consists of the symbol representing the element and an arrangement of dots that usually shows

(A) the atomic number

(B) the atomic mass

(C) the number of neutrons

(D) the electrons in the outermost energy level

9. Chlorine is represented by the Lewis structure . The atom that would be represented by an identical electron-dot arrangement has the atomic number

(A) 7

(B) 9

(C) 15

(D) 19

10. Radioactive changes differ from ordinary chemical changes because radioactive changes

(A) involve changes in the nucleus

(B) are explosive

(C) absorb energy

(D) release energy

11. Isotopes of uranium have different

(A) atomic numbers

(B) atomic masses

(C) numbers of planetary electrons

(D) numbers of protons

12. Atoms of 235U and 238U differ in structure by three

(A) electrons

(B) isotopes

(C) neutrons

(D) protons

13. The use of radioactive isotopes has produced promising results in the treatment of certain types of

(A) cancer

(B) heart disease

(C) pneumonia

(D) diabetes

14. The emission of a beta particle results in a new element with the atomic number

(A) increased by 1

(B) increased by 2

(C) decreased by 1

(D) decreased by 2

The following questions are in the format that is used on the SAT Subject Test in Chemistry.

Questions 15–19

Use this abbreviated periodic table to answer the following questions.

15. Which neutral atom has an outer energy level configuration of 3s1?

16. An atom of which element shows the greatest affinity for an additional electron?

17. Which element is the most active metal of this group?

18. Which element has the lowest electronegativity of this group?

19. Which element has an outer orbital configuration of 2s2 2p2?

Directions:

Every question below contains two statements, I in the left-hand column and II in the right-hand column. For each question, decide if statement I is true or false and whether statement II is true or false, and fill in the corresponding T or F ovals in the answer spaces. *Fill in oval CE only if statement II is a correct explanation of statement I.

I

 

II

20. Si, with an atomic number of 14, will probably exhibit an oxidation number of +4 in a compound

BECAUSE

silicon is an element that has amphoteric properties.

21. Nonmetallic atoms have larger ionic radii than their atomic radii

BECAUSE

nonmetallic atoms generally gain electrons to form the ionic state and increase the size of the electron cloud.

22. Elements in the upper right corner of the Periodic Table form acid anhydrides

BECAUSE

nonmetallic oxides react with water to form acid solutions.

*Fill in oval CE only if II is a correct explanation of I.

Answers and Explanations

1. (C) The two main parts of the atom are the nucleus and its energy levels.

2. (B) The principal quantum numbers start with the value of 1 to represent the first level.

3. (A) The letter s is used to represent the first orbital that can hold two electrons.

4. (A) The sublevel d has five orbitals that each can hold two electrons, totaling ten electrons.

5. (C) Each orbital can only hold two electrons.

6. (B) The mass number is the total of the number of protons and neutrons, which in this case is nine.

7. (D) The second principal energy level has an s orbital and three p orbitals, making a total of four.

8. (D) The Lewis electron-dot notation shows the symbol and the outermost energy-level electrons, which are referred to as the valence electrons.

9. (B) Chlorine is a member of the halogen family found in group 17. The other element in the same family would be the element with the atomic number 9, fluorine.

10. (A) Radioactive changes differ because they involve changes in the nucleus.

11. (B) Isotopes differ in their atomic mass because of differences in the number of neutrons.

12. (C) These two isotopes, 235U and 238U, differ in their atomic mass by 3 neutrons.

13. (A) Radioactive isotopes have been successful in the treatment of certain cancers.

14. (A) A beta particle emission causes an increase of 1 in the atomic number.

15. (B) Because Na (sodium) has the position shown, it has the atomic number 11. The electron configuration is 1s2 2s2 2p6 3s1.

16. (E) Fluorine has seven electrons in its outer energy level and needs only one more to complete its outer energy level octet. It therefore has the greatest affinity for one more electron.

17. (C) The most active metal of the group is found in the lower left-hand corner. Because its outer energy level is furthest from the nucleus and these are the most loosely held electrons, it is the most likely to lose an electron.

18. (C) The element that has the lowest electronegativity will be in the lower left corner. For this group, it is K.

19. (D) The element that has this configuration is carbon, which has six electrons. The first two are in the first level, and the next four are in the second level, as 2s2 2p2.

20. (T, T) Both statements are true, but statement II does not explain statement I.

21. (T, T, CE) Because nonmetallic atoms gain electrons to form ions, the additional negative charge of the added electrons increases the size of the ion. This occurs because of the increased repulsion of the additional negative charge(s) and additional shielding from the positively charged nucleus.

22. (T, T, CE) Elements found in the upper right corner of the Periodic Table are nonmetals that form oxides and react with water to form acids. An example is sulfur that forms sulfur trioxide, and this reacts with water to form sulfuric acid.