1
COPPIN STATE COLLEGE DEPARTMENT OF NATURAL SCIENCES
Name ______
Last First
Chemistry 103-101 Examination II (Chapter 2 and part of 3- The Composition and Structure of the Atom and Elements, Atoms, Ions, and the Periodic Table)
October 8, 2003: Time 60 minutes.
Dr. Alfred N. Amah
This examination consists of two parts: Part A (56 points) consists of 14 multiple choice questions; carefully read each question and all the possible responses. Choose the correct answer by cycling the alphabet before your choice. Part B (44 points) contains short structured questions. Carefully read each question and provide the response. Some very useful information are provided at the end of the examination along with a Periodic Table. Please turn in all examination papers. GOOD LUCK!
Part A (56 points). Multiple Choice Questions.
1. Which one of the following is one of the postulates of Dalton's atomic theory?
a. All atoms have atomic nuclei.
b. All atoms have electrons.
c. Atoms of different elements have different masses.
d. The isotopes of a given element differ only in mass.
2. What is responsible for almost all of the mass of an atom?
a. nucleus
b. electron
c. electons and protons
d. atomic number
3. What is true about an atom of an element with a mass number of 19 and an atomic number of 9?
a. The atom has 9 neutrons
b. The atom has 10 electrons
c. The atom has 10 protons
d. The atom has 10 neutrons
4. Isotopes are atom of the same element that have?
a. The same mass
b. The same number of electrons
c. Different number of neutrons.
d. Different number of protons.
5. What is the electron configuration (main levels) of magnesium (mass number 24; atomic number, 12)?
a. 2 10
b. 2 8 8 6
c. 2 6 4
d. 2 8 2
6. When one construct the electron configuration of the element with atomic number 19, the last electron to be placed into an energy level goes into which main level number?
a. 1
b. 2
c. 3
d. 4
7. The number of electrons in the highest energy level of an element (valence electrons) represent?
a. period of the element
b. group number of the element
c. atomic number of the element
d. none of the above
8. The Periodic law state that the properties of the elements are periodic functions of what features of the element?
a. atomic masses
b. atomic numbers
c. mass numbers
d. period numbers
9. Horizontal rows of the element in the periodic table are called?
a. families
b. groups
c.representative elements
d. periods
10. The main energy level 2 represented by (L) have?
a. one sublevel
b. two sublevels
c. two electrons
d. none of the above
11. The maximum number of electrons that can go in the main energy level 3 represented by M are ?
a. 8
b. 10
c. 18
d. 32
12. The electron configuration of an elelment is written:
1s2 2s2 2p6 3s1; therefore:
a.Its atomic number is 12
b. Its atomic number is 11
c. Its atomic mass is 11
d. It is a gas
13. The number of valence electrons in the element with the electron configuration written 1s2 2s2 2p6 is:
a. 2
b. 6
c. 8
d. none of the above
14. The number of electrons that may occupy a p subshell are?
a. 2
b. 6
c. 8
d. 10
PART B (44 POINTS). Short Structured Questions. For each of the following problems show your calculation and setup. In both your setup and answer show units and follow rules of significant figures.
1. (Credit 8) Provide the electron configuration for the elements
a. 3Li:
b. 9F:
Question #2Total 10 points
A. Copper, a metal known since ancient times, is used in electrical cables and pennies, among other things. It has two stable isotopes. Isotope 1 (69.09%) has a mass of 62.93 amu and isotope 2 (30.91%) has a mass of 64.9278 amu. The percentages in parentheses denote the relative abundances. Calculate the average atomic mass of copper.
Question #3 Total 16 points
A. Write the appropriate (nuclear) symbol for each of the following:
a. Z=14, A=7 ______
b. Z=28, A=14 ______
Z=Mass number and A=Atomic number
B. Name the three isotopes of hydrogen and write the nuclear symbol for each isotope.
1. _____ (Name) ______
2. _____ (Name) ______
3. _____ (Name) ______
Question #4 Total 10 points
C. Indicate the atom in each pair that is more metallic.
a. Lithium or Nitrogen ______
b. Argon or Aluminum ______
c. Barium or Boron ______
D. Identify the group and the period in which each of the following elements is formed.
a. Ne Group ______Period ______
b. Rb Group ______Period ______
c. Br Group ______Period ______
E. Identify each of the following elements:
a. The first member of the third period ______
b. Second alkali metal ______
Some Useful Information
Principal energy levels: 1 2 3 4 5 6
______
K L M N O P
Sub energy levels s s, p s, p, d s, p, d, f s, p, d, f, g, etc.
Maximum number of electrons that can go into each principal energy level = 2n2