Chapter 7 assessment
Name the three crystal arrangements of closely packed metal atoms. Give an example of a metal that crystallizes in each arrangement.
1. Body-centered cubic (Chromium) 2. Face-centered cubic (Gold) 3. Hexagonal close-packed (Zinc)
Which of the following pairs of atoms would you expect to combine chemically to form an ionic compound?: a. Li and S b. O and S c. Al and O d. F and Cl e. I and K f. H and N
All, except e.
Explain why molten MgCl2 does conduct an electric current although crystalline MgCl2 does not.
Because it is a liquid, and not a solid.
Explain briefly why metals are good conductors of electricity.
Because they are conductor elements.
Why do nonmetals tend to form anions when they react to form compounds?
Because they have full valence shells.
Name some alloys that you have used or seen today.
Brass
Explain why ionic compounds are electrically neutral.
They are electrically neutral, because they are two or more atoms compounded together, and that makes them even, because it could be two atoms that are compounded where one is short five electrons (-5) and the other has five extra electrons (+5).
Most ionic substances are brittle. Why?
They are two or more atoms compounded and are mostly a metal and a highly reactive liquid.
Define valence electrons.
Valence electrons are electrons that are in the outer shell of the atom.
State the number of electrons either lost or gained in forming each ion: a. Br^(-1) b. Na^(+1) c. As^(-3) d. Ca^(+2) e. Cu^(+1) f. H^(-1)
a. lost 1 b. gained 1 c. lost 3 d. gained 2 e. Gained 1 f. lost 1
Which of the following pairs of elements will not form ionic compounds?: a. sulfur and oxygen b. sodium and calcium c. sodium and sulfur d. oxygen and chlorine
b
Describe two ways that an ion forms from an atom.
An ion forms when an atom or group of atoms loses or gains electrons.
Write the formula for the ion formed when each of the following elements loses its valence electrons: a. aluminum b. lithium c. barium d. potassium e. calcium f. strontium
a. 1s^(2)2s^(2)2p^(5)3s^(1) b. 1s^(1) c. 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)4d^(10)4p^(6)5s^(2)5d^(10)5p^(1) d. 1s^(2)2s^(2)2p^(6)3s^(2)3p^(3) e. 1s^(2)2s^(2)2p^(6)3s^(2)3p^(4) f. 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)4d^(10)4p^(2)
What is the formula of the ion formed when the following elements gain or lose valence electrons and attain noble-gas configurations?: a. sulfur b. sodium c. fluorine d. phosphorus
a. 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6) b. 1s^(2)2s^(2)2p^(6) c. 1s^(2)2s^(2)2p^(6) d. 1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)
How many electrons must each atom lose to attain a noble-gas electron configuration?: a. Ca b. Al c. Li d. Ba
a. 2 b. 3 c. 1 d. 2
How many electrons does each atom have? What group is each in? a. nitrogen b. lithium c. phosphorus d. barium e. bromine f. carbon
a. 7 b. 3 c. 15 d. 56 e. 35 f. 6
How many electrons must be gained by each of the following atoms to achieve a stable electron configuration?: a. N b. S c. Cl d. P
a. 8 b. 0 c. 0 d. 0
Write the formula for the ions in the following compounds: a. KCl b. BaSO4 c. MgBr2 d. Li2CO3
a. [Ar]4s^(2)4d^(2) b. [Kr]5s^(2)5d^(4) c. [Kr]5s^(2) d. [Ne]3s^(2)3p^(1)
Name each ion in problem 31. Identify each as an anion or cation.
a. anion b. cation c. anion d. cation e. cation f. anion
Identify the kinds of ions that form each ionic compound: a. Calcium Fluoride, CaF2 b. Aluminum Bromide, AlBr3 c. Lithium Oxide, Li2O d. Aluminum Sulfide, Al2S3 e. Potassium nitride, K3N
a. anion b. cation c. cation d. anion e. anion
