1988 Avogadro Exam: Part 1

To celebrate the 30th year of the Avogadro Exam we are reprinting questions from the first exam in 1988 in this and upcoming issues. The exam was, and is, aimed at grade 11 chemistry students. Before you think the first question is easy, note students had only a periodic table with just the elemental symbols (shown right, reduced-size) as their resource — no atomic numbers or masses. Now students are given a periodic table with this information along with a data sheet. The number of questions has not changed — still 40 questions to answer in 75 minutes.

Consider registering your students to write the 2017 Avogadro Exam https://uwaterloo.ca/chemistry/exams in May 2017. See Chem Dates, back cover for details.

1. Which quantity of lead weighs the most?
   1. 1 cm³
   2. 207.2 g
   3. 6.02 x 10²³ atoms
   4. one gram-atomic weight
   5. 22.4 mol
2. The letter Z represents any one of several atoms. Choose the one correct statement:
   1. The number of protons in ⁷₃Z is 4.
   2. The number of neutrons in  ³₂Z is 3.
   3. ⁷₃Z and ⁷₄Z are isotopes of one element.
   4. ⁴₂Z means that Z has atomic number 2 and mass number 4.
   5. Neutral atoms of ⁶₃Z will have 9 electrons.
3. An element, X, has only two isotopes, of relative masses 80.01 and 83.02, and the relative atomic mass of a natural sample of the element is 81.82. What is the percentage abundance of atoms of the lighter isotope?
   1. 30%   
   2. 40%
   3. 50%
   4. 60%
   5. 70%        
4. A beta particle is
   1. the nucleus of a helium atom
   2. negatively-charged and mass number zero
   3. also called a photon
   4. a pair of electrons
   5. a negatively-charged hydrogen ion
5. The element below which belongs to a different group of the periodic table than any of the others shown is
   1. aluminum      
   2.  beryllium
   3.  calcium
   4.  lithium
   5. sodium
6. The compound named sodium chlorate(V) has the formula
   1. Na₅ClO₂   
   2. NaClO₂ 
   3. NaClO₃
   4. NaClO₄
   5. NaClO₅
7. The highest oxidation state for sulfur in its compounds is
   1. +12   
   2. +10
   3. +8
   4. +6
   5. +4     
8. The most ionic compound below is
   1. LiI        
   2. NaBr
   3. CsF
   4. Rb₂S
   5. KCl  
9. A neutral atom whose lowest-energy electronic configuration is [noble gas] 7s² 6d¹⁰ 7p⁴ belongs to the same group as
   1. oxygen  
   2. beryllium
   3. carbon
   4. titanium
   5. chromium       
10. The second ionization energy of an element, M, in the gaseous state, is the energy required to remove one mole of electrons from
    1. one-half of a mole of M atoms
    2. one mole of M atoms
    3. one mole of M⁺ ions
    4. one mole of M²⁺ ions
    5. one mole of M³⁺ ions   

Answers

1.    A                                    6.            C

2.    D                                    7.            D

3.    B                                    8.            C

4.    B                                    9.            A

5.    A                                    10.          C