Name: ______
CHEMISTRY 1151 SUMMER SESSION 2004
EXAM #2
This exam is twenty questions long. Please read through all of the questions and ask about anything you do not understand. You will have one hour and 15 minutes to complete this exam. Exams will be picked up at the end of the class period. No late exams will be accepted.
You are allowed to use a calculator. Included in this exam is a periodic table, which should be stapled to the back of the exam.
CHEATING IS NOT ALLOWED. ANYONE CAUGHT CHEATING WILL BE SENT TO THE JUDICARY BOARD FOR REVIEW.
The exam is worth 100 points. Each question is labeled with its exact point value. Be sure to answer all of the questions on the exam.
Good Luck! 1.) (5 points) Fill in the following table:
Name Charge Mass Proton +1 1 amu
Electron -1 0 amu
Neutron 0 1.00 amu
2.) (18 points) Fill in the following table:
Symbol Protons Electrons Neutrons Mass Atomic Number Number 174Yb 70 70 104 174 70
141Pr 59 59 82 141 59
104Ru 44 44 60 104 44
12 12 12 24 12 24Mg
3.) (3 points) Fill in the blanks with protons, neutrons and electrons:
Isotopes are atoms with the same number of _protons______and
___electrons______but different numbers of ____neutrons______.
4.) (2 points) Write the standard isotopic notation for an atom with 14 protons, 14 electrons and 16 neutrons.
30 14Si 5.) (2 points) The chemical properties of an element are determined by the number of electrons in the ____B______. a.) Energy level closest to the nucleus b.) Outermost energy level c.) Second energy level d.) None of these
6.) (10 points) Chlorine exists in two isotope forms, 35Cl (mass 34.9689 amu) and 37Cl(mass 36.9659 amu). The atomic mass of chlorine is 35.453 amu. Calculate the percent abundance of each isotope.
35.453 = 34.9689(x) + 36.9659(1-x)
35.453 = 34.9689x + 36.9659 - 36.9659x
-1.5129 = 34.9689x – 36.9659x
-1.5129 = -1.997x 0.7575 = x
35 Cl is 75.75% and 37Cl is (1-0.7575= 0.2424) 24.24%
7.) (3 points) Give an example of heat energy being absorbed and re-emitted as light energy.
A light bulb
8.) (2 points) Bundles of energy absorbed or emitted by electrons are called
___Photons______? 9.) (3 points) Describe the ground state configuration of a lithium atom. What changes could take place if the lithium atom were in an excited state?
Li 1s22s1 All of the electrons are in the lowest orbitals
Excited state electrons moves further away from the nucleus for example 1s22p1 The 2s subshell is empty in the excited state
10.) (6 points) List all of the subshells contained in the fourth energy level of an atom. a. List the maximum number of electrons each subshell can hold.
N =4 s p d f Max electrons 2 6 10 14
11.) (3 points) In the periodic table, a vertical column is called a
___family or group______.
12.) (3 points) List the following elements in order of increasing atomic radius: In, P, I, Sb, and As
P 13.) (4 points) Which element in each pair has the smaller ionization potential? a.) K or Ca K b.) O or Se Se 14.) (2 points) Choose the correct answer: An Al+3 ion is an aluminum atom that has ______D______. It is called a ______D______. a.) gained three protons anion b.) lost three protons cation c.) gained three electrons anion d.) lost three electrons cation 15.) (2 points) Fill in the blank: A negative ion is an atom (or a group of atoms) that has ______C______. a.) Gained a proton b.) Lost a proton c.) Gained an electron d.) Lost an electron 16.) (6 points) Write the electron – dot structure for each of the following elements a.) F b.) Ca c.) C 17.) (6 points) Write the electron dot structure for each of the following compounds: a.) HCN H-C≡N b.) C2H6 18.) (10 points) Label each of the following compounds as being bonded ionically or covalently: a.) MgO ionic b.) BaCl2 ionic c.) BaO ionic d.) CaF2 ionic e.) SO2 covalent 19.) (6points) Label each of the following as being polar or nonpolar. a.) H2 nonpolar b.)NO polar c.) HCl polar 20.) (4points) Label the bonds in the molecule below as being polar or nonpolar. Is the molecule polar? Explain your answer. C-Cl bond is polar C-H bond is weakly polar C=C bond is nonpolar Due to the structure of the molecule, it will be polar because the Cl pulls on the C which pulls on the H and the dipole will go trough the middle of the molecule facing towards the Cl (negative end.)