CEM 141 PRACTICE EXAM QUESTIONS WITH VERIFIED ANSWERS

CEM 141 PRACTICE EXAM QUESTIONS WITH VERIFIED ANSWERS Which has a larger atomic radius? Mg or Ar? Why? A. Mg, because it is a metal. B. Mg, because its valence electrons are not as strongly attracted towards the nucleus as those in Ar. C. Ar, because it is a heavier element. D. Ar, because it has more electrons and they repel each other. B Out of Na+, Mg2+, Ne, and F- which has the smallest radius? A. Na+ B. Mg2+ C. Ne D. F- B When and where were the carbon and oxygen atoms in your body created? A. In plants as they were growing B. During the big bang C. Within stars and stellar explosions D. During the course of digesting your food C Iodine and silicone dioxide are both solid at room temperature. Which has a higher melting point and why? A. I2 because it is heavier and therefore has the largest LDFs B. I2 because it is an element C. Silicon dioxide because to melt it you would have to break covalent bonds D. Silicon dioxide, because it is a compound C Does one molecule of water have a boiling point? A. yes B. no B Why do covalent bonds form? I. Because atoms want to share electrons. II. Because electrons from one atom are attracted to the nucleus of another atom. III. Because atoms want an octet of electrons around them. IV. Because the formation of a bond results in a stable system that would require the input of energy to change. A. I B. II and IV C. III D. I and II B Which of the following are correct statements? I. Covalent bonds are interactions WITHIN MOLECULES. II. Covalent bonds are interactions BETWEEN SEPARATE MOLECULES. III. LDF's are typically interactions BETWEEN SEPARATE MOLECULES, but can occur within a single large molecule.