PS 100 - Ch. 22

When sodium (Na) and Chlorine (Cl) form table salt (NaCl) the chlorine atoms A. turn into chlorine molecules B. become positively charged chlorine ions C. become negatively charged chlorine ions D. move up (right) one spot in the periodic table, towards sodium E. move down (left) one spot in the periodic table, towards the noble gases

C. become negatively charged chlorine ions

In Lesson 20, a magnesium strip was used to ignite the thermite reaction. When magnesium is placed in a flame from a small blow torch, it burns quite brightly forming magnesium oxide, a salt that contains one magnesium for every oxygen. In the following questions you will be asked to provide some details of the chemical processes involved in a reaction between magnesium and oxygen. How many more electrons does unbound oxygen need to fill its 2nd shell? (You may find it helpful to draw the energy well on scratch paper.) Select one: a. 1 b. 2 c. 6 d. 8 e. None, the 2nd shell is full.

b. 2

What happens to the valence electrons as the product (MgO) is formed? Select one: a. The orbitals spread out into the whole solid and overlap. b. The magnesium atoms' valence electrons are effectively transferred to oxygen. c. The oxygen atoms' valence electrons are effectively transferred to magnesium. d. The orbitals of both atoms' valence electrons change shape so that the electrons are shared equally between the atoms. e. The electrons move to new orbitals that are higher in energy than the individual atomic orbitals.

b. The magnesium atoms' valence electrons are effectively transferred to oxygen.

Which of the following is a correct and balanced equation showing the reaction of calcium and oxygen? (While several of the equations may be balanced, only one has the correct products and reactants as well as being correctly balanced.) a. Ca + O22 = CaO b. Ca + O22 = CaO22 c. 2Ca + O22 = 2CaO d. 4Ca + O22 = 2Ca22O e. Ca + O22 = Ca22O

c. 2Ca + O22 = 2CaO

What is the charge of iron (Fe) in the compound Fe22O33? Select one: a. -3 b. -2 c. +2 d. +3

d. +3

What happens to the entropy of the universe as the products are formed? Select one: a. The total entropy stays the same. b. Thermal energy is converted into electromagnetic energy resulting in a decrease in total entropy. c. Chemical bonds are formed resulting in a decrease in total entropy. d. Chemical potential energy is converted into kinetic energy resulting in a decrease in entropy. e. Chemical potential energy is converted into thermal energy resulting in an increase in entropy.

e. Chemical potential energy is converted into thermal energy resulting in an increase in entropy.

Which of the following ionic compounds is most likely to be colored (use the periodic table)? A. KBr B. HgS C. NaCl D. MgO E. none of the above will be colored

B. HgS

Which of the following would best describe the room temperature characteristics of the magnesium oxide? Select one: a. Brittle, opaque, solid. b. Electrically conducting alloy. c. Transparent gas. d. A malleable solid. e. Brittle, transparent, electrically non-conducting solid.

e. Brittle, transparent, electrically non-conducting solid.