Chapter 7 Chemistry Test

Give the number of valence electrons in the atom cesium

1

Give the number of valence electrons in the atom rubidium

1

Compare the oxyanions sulfate and sulfite.

Both oxyanions are composed of sulfur and oxygen. Sulfate SO4 has more oxygen atoms than sulfite, SO3. The prefix -ite is used to indicate one less oxygen atom. Both ions have the same oxidation number of 2-.

Explain why calcium can form a Ca2+ ion but not a Ca3+ ion

Ca, [Ar]4s2, will lose two electrons. If it loses an inner 3p electron, it is unstable.

Give the formula for each ionic compound. d. calcium phosphate

Ca3(PO4)2

Which compounds are not likely to occur: CaKr, Na2S, BaCl3, MgF? Explain your choices.

CaKr, because Kr is a noble gas; BaCl3 and MgF, because charges are not balanced

Describe a metallic bond.

Each positive metal ion is attracted to delocalized valence electrons.

Give the formula for each ionic compound. b. iron(III) chloride

FeCl3

Which are correct formulas for ionic compounds? For those that are not correct, give the correct formula and justify your answer.

a. AlCl AlCl3; one Al3 ion bonds to three Cl ions

Discuss the formation of ionic bonds.

A positive ion is attracted to a negative ion and lattice energy is released.

Discuss how an ionic compound is named

1. Name the cation first and the anion second. 2. Monatomic cations use the element name. 3. Monatomic anions take their name from the root of the element name plus the suffix -ide. 4. Group 1 and group 2 metals have only one oxidation number. Transition metals and metals on the right side of the periodic table often have more than one oxidation number. 5. If the compound contains a polyatomic ion, simply name the ion.

Give the number of valence electrons in the atom strontium

2

Give the number of valence electrons in the atom zinc

2

Give the number of valence electrons in the atom gallium

3

Briefly explain why metallic alloys are made.

Alloys have slightly different properties than those of the pure metal they are mixed from. Some alloys have increased strength and are harder than the pure metal.

Briefly explain why steel, an alloy of iron, is used to build the supporting structure of many buildings.

Iron forms a strong metallic bond, giving solid iron hardness and strength.

Explain how an anion of nitrogen forms

N gains three electrons, forming N3-, which has the stable electron configuration of Ne.

Give the formula for each ionic compound. a. sodium sulfide

Na2S

Give the formula for each ionic compound. c. sodium sulfate

Na2SO4

Explain why potassium does not bond with neon to form a compound.

Neon already has an octet in its outer energy level; it is already stable.

What does the term electrically neutral mean when discussing ionic compounds?

The number of electrons lost is equal to the number of electrons gained.

Explain why the term delocalized is an appropriate term for the electrons involved in metallic bonding.

They are free to move; the electrons are not held to any specific atom.

Discuss the formation of an ionic bond between zinc and oxygen.

Zn will lose its outer 4s electrons, forming Zn2+. Oxygen will gain the two electrons forming O2-. Zn2+ attracts O2-, forming ZnO.

Give the formula for each ionic compound. e. zinc nitrate

Zn(NO3)2

Name each ionic compound. c. AlPO4

aluminum phosphate

Which are correct formulas for ionic compounds? For those that are not correct, give the correct formula and justify your answer.

b. Na3SO4 Na2SO4; two Na ions bond to SO4

Name each ionic compound. d. Ba(OH)2

barium hydroxide

Name each ionic compound. b. BaS

barium sulfide

Name each ionic compound. a. CaO

calcium oxide

binary ionic compound

contain only 2 different elements

Chromium, a transition metal used in chrome plating, forms both the Cr2+ and Cr3+ ions. Write the formulas for the ionic compounds formed when each of these ions react with fluorine and oxygen ions.

fluorine: CrF2, CrF3; oxygen: CrO, Cr2O3

Name each ionic compound. e. Sr(NO3)2

strontium nitrate

ionic bond

the electrolastic force that holds oppositely charged particles together in an ionic compound