Honors Chemistry: Test Objectives for Unit 10a: Ionic & Metallic Bonding
Name: _____________________________________________ Date: ___________

Know that a chemical bond is the force of attraction between two atoms that holds them together.

Recognize that atoms attain a stable valence electron configuration by bonding with other atoms. Noble gases have stable valence electron configurations (full octets) and tend not to bond.

Understand that in an ionic bond , atoms achieve a noble gas configuration by transferring electrons . o Metal atoms lose electrons to form positive ions ( cations ) that are smaller than the parent atom. o Nonmetal atoms gain electrons to form negative ions ( anions ) that are larger than the parent atom.

Understand that the electrostatic force that holds oppositely charged ions together in an ionic compound is an ionic bond .

Know that binary compounds contain two elements, but may contain more than two atoms.
(NaCl and Al
2
O
3
are both binary compounds.) The names of binary compounds end in “ide.”

Predict the bond type of a chemical substance from its chemical formula. o Binary ionic compounds have metal + nonmetal. o Binary covalent compounds have two nonmetals.

Draw Lewis dot diagrams for atoms, ions, and ionic compounds. Be able to show how the electrons are transferred in bond formation.

Describe the structure of ionic substances: positive and negative ions (cations and anions) are arranged in a repetitive 3-D pattern called a crystal lattice . The ions are attracted to each other by very strong electrostatic forces. The formation of the lattice maximizes the interactions between oppositely charged ions and lowers the energy of the system.

Memorize: Breaking Bonds aBsorbs energy. Making bonds Liberates energy.

Draw a simple diagram that shows the change in potential energy that accompanies stable bond formation.

Define lattice energy and explain its significance.

Recall the relationship between stability and potential energy. As potential energy increases, stability decreases and vice versa.

Understand the relationship between structure, bonding, and properties for ionic compounds.

List the properties of ionic substances. (Hard, brittle, high melting & boiling points, high H f
& H v
, low vapor pressure, tend to be soluble in water, and conductive in the liquid phase & in aqueous solution.)

Explain why ionic compounds will NOT conduct electricity in the solid phase but will conduct electricity in the molten state or in solution.

Explain why ionic compounds will cleave in preferential directions.

Understand that most chemical bonding is neither purely ionic nor purely covalent.

Given several compounds, predict which one will have the greatest ionic character based on electronegativity (EN) differences. o The larger the EN difference between the two atoms in the bond, the greater the ionic character of the bond. o Classify bonding type according to electronegativity differences. Rule-of-thumb: If the EN difference is less than 1.7, the bond is generally considered covalent; greater than 1.7, the bond is generally considered ionic.

Predict the charge of an A-Group or representative element when it is in an ionic compound from the position of the element in the Periodic Table.


Given two elements, a metal (A group) and a nonmetal, write the chemical formula of the binary ionic compound they form. o Use oxidation numbers and the criss-cross rule to help explain the formula. o Explain how the electrons are transferred between the atoms.

Write formulas for ionic compounds containing transition metals that have multiple positive oxidation states given the oxidation state of the metal ion.

Distinguish between monatomic ions and polyatomic ions. o Monatomic ion is one atom that has gained or lost electrons and hence carries a charge. o Polyatomic ion is a group of atoms covalently bonded together that carries a charge and hence can participate in ionic bonding with other oppositely charged ions.

Recognize formulas that contain polyatomic ions.

Write correct formulas for ionic compounds containing polyatomic ions . Use the criss-cross method for determining subscripts in compounds with polyatomic ions.

List the rules for assigning oxidation numbers.

Give the oxidation number for each element in the formula of a compound.

Write the Stock System name for binary ionic compounds and compounds containing polyatomic ions given the formula of the compound. Understand that the names of compounds containing metals which have more than one possible oxidation state will contain roman numerals which specify the charge on the metal ion in that particular compound. o NaCl is sodium chloride. Na always has a +1 charge. o CrCl
3
is chromium ( III ) chloride. Cr has several possible charges. In this compound, the Cr has a +3 charge.

Write the formula for ionic compounds given the Stock System name.
 Recognize that the names of most polyatomic ions end in “ite” or “ate,” and that the names of three unfortunate polyatomic ions end in “ide”. (CN
-1
or cyanide, OH
-1
or hydroxide, and O
2
-2 or peroxide.) For series of polyatomic ions containing differing numbers of O atoms, the
“ate” form contains one more O than the “ite” form.

Define the term metallic bond and list the properties of metallic substances. o Understand the term “ sea of mobile electrons
.” Describe the electron-sea model of metallic bonding. o Explain the trends for melting point in the s-block using the electron-sea model. o Describe the relationship between structure and properties for metallic substances.
Explain why metals are good electrical conductors, good heat conductors, and why metal surfaces are shiny.

Metals are similar to ionic compounds in that they form a lattice. o Metals have a crystal lattice formed from cations. The valence electrons are the
“glue” that hold the cations together. o Ionic compounds have a crystal lattice formed from both cations and anions. o Explain why metals are malleable and ductile, while ionic compounds are brittle.

Metals are similar to covalent compounds in that the metal atoms share their valence electrons. Atoms in covalent substances share the bonding electrons.