Unit 4: Inorganic Nomenclature

Editor: Hannah Valley

Chapter 7-9 Summary:

-to find the number of valance electrons in an atom of a representative element, simply look at its group number
-atoms of the metallic elements tend to lose their valance electrons, leaving a complete octet in the next-lowest energy level.
-atoms of some nonmetallic elements tend to gain electrons to achieve a complete octet
-an atom's loss of valance electrons produces a positively charged cation
-the gain of electrons by a neutral atom produces negatively charged ions
Ionic Bonds and Ionic Compounds
-although they are composed of ions, ionic compounds are electrically nuetral
-most ionic compounds are crystalline solids at room temperature and generally have high melting points
ionic compounds conduct an electric current when dissolved in water or melted
Bonding in Metals
-the valance electrons of metal atoms can be modeled as a sea of electrons
-metal atoms are arranged in very compact and orderly patterns
-alloys are important because their properties are ofter superior to those of their component elements
Molecular Compounds
-tend to have relatively low melting and boiling points
-a molecular formula shows how many atoms of each element a molecule contains
Covalent Bonding
-electron sharing occurs so that atoms attain the configurations of noble gases
-an electron dot structure shows the shared electrons of a covalent bond by a pair of dots
-atoms form double or triple bonds by sharing two or three pairs of electrons
-in a coordinate covalent bond, the shared electron pair comes from a single atom
-a large bond dissociation energy corresponds to a strong covalent bond
-octet rule not satisfied with molecules with odd number or one less or more that a complete octet--eight
Bonding Theories
-just as an atomic orbital belongs to a particular atom, a molecular orbital belongs to a molecule as a whole
-VSEPR theory says repulsion between election pairs causes molecules to adjust shape to keep valance pairs as far as possible
Polar Bonds and Molecules
-when different atoms bond, the more electronegative atom attracts electrons more strongly and acquires a slight negative charge
-polar molecules between oppositely charged metal plates tend to become oriented with respect to the positive and negative plates
-the attraction between molecules is weaker than either an ionic or covalent bond
-melting a network solid requires breaking covalent bonds throughout the solid
Naming Ions
-when the metals in groups 1A, 2A and 3A lose electrons, they form cations with positive charges equal to their group number
-the charge of any ion of a group A nonmetal is determined by subtracting 8 from the group number
-the charges of cations of many transition metal ions cumt be determined from the number of electrons lost.
-when a cation can have more that one ionic charge, a Roman numeral is used in the name to indicate the charge
the names of most polyatomic ions end in -ite or -ate

Group 1: Pages 187-203

Coeditor: Lauren Altmeyer

Pages 187-188: valence electrons and the octet rule by Erin Garrity

Pages 189-192: formation of cations and formation of anions by Lauren Bedard

Ex: Magnesium: group 2A- 2 valence electrons
Cations of group 1A: charge of 1+
Cations of group 2A: charge of 2+
-The atoms lose enough electrons to attain the electron configuration of a noble gas
-Transition metals: charge of cation may vary
-Some ions formed by transition metals do not have noble-gas electron configurations à exceptions to the octet rule (example: silver)
-Ions with charges of 3 or greater are uncommon

Formation of Anions Anion: atom or group of atoms with a negative charge; typically changes in -ide -The gain of negatively charged electrons by a neutral atom produces an anion (name of an anion of a nonmetallic element is NOT the same as the element name) -Atoms of nonmetallic elements attain noble-gas electron configurations more easily by gaining electrons than by loosing them because they have relatively full valance shells. -Chloride ion: anion with a single negative charge -Halide ions: the ions that are produced when atoms of chlorine and other halogens gain electrons -All halogen atoms have 2 valence electrons and need to gain only 1 to achieve electron configuration.

Pages 194-195: formation of ionic compounds by Lauren Altmeyer

Formation of Ionic Compounds
-ionic compounds are compounds composed of cations and anions
-ionic compounds are usually composed of metal cations and nonmetal anions
-ionic compounds are electrically neutral

Ionic Bonds
-anions and cations have opposite charges and attract eachother by means of electrostatic forces
-ionic bonds are the electrostatic forces that hold ions together in ionic compounds

Formula Units
-ionic compounds have to be composed of equal numbers of anions and cations
-a chemical formula shows the kinds and numbers of atoms in the smallest representative unit of a substance
-because an ionic compound exists as a collection of positively and negatively charged ions arranged in repeating patterns, its chemical formula refers to a ration known as a formula unit
-formula unit is the lowest, whole-number ration of ions in an ionic compound
although ionic charges are used to derive the correct formula, they are not shown when you write the formula unit of the compound

In Sodium chloride:
-sodium has a single valance electron, chlorine has seven
-when sodium and chlorine react to form a compound, the sodium atom gives its electron to the chlorine atom, thus stabilizing both and making a one-to-one ratio
-sodium chloride is composed of equal numbers of sodium cations (Na+) and chloride anions (Cl-)
-the ions in solid sodium chloride are arranged in an orderly pattern, making a continuous array of ions
Ionic Bond by: Lauren Altmeyer
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Ionic Bonds by: Lauren Altmeyer

Pages 196-198: properties of ionic compounds by Seamus Cuddy

-Most ionic compounds are crystalline solids at room temperature
Ions of crystals are arranged in repeating 3D patterns

external image pyrite2.jpg
" Arrangement of Crystals" By Mark Cuddy

The typical crystal is clusters of one ion surrounded by six other ions of the same atom. Each of theses ions are attracted strongly to each of its neighbors and repulsions are minimized
~These large attractive forces result in a very stable structure
~ionic compounds generally have high melting points
The COORDINATION NUMBER of an ion is the # of ions of opposite charge that surround the ion in a crystal
Example: An Na+ ion is surrounded by six Cl- , therefore Na+ has a coordination # of 6

Ionic Compounds can conduct an electric current when melted or dissolved in water. When ionic compounds are melted, the orderly crystal breaks down.
If a voltage is applied across the molten mass, cations migrate freely to one electrode and anions migrate to the other. This allows electricity to flow between the electrodes through an external wire.
~Ionic Compounds conduct electricity if they're dissolved in water because the ions are free to move about separately.

Pages 201-203: metallic bonds/properties and crystalline structure of metals and alloys by Erika Paiva

Metallic Bonds and Metallic Properties
- Metallic bonding is the attraction of free-floating valance electrons for the positively charged metal ions.
- Metallic bonds hold metal together
- The valence electrons can move around freely, which is why they can be referred as the “sea of electrons.”
- Metals have many physical properties, such as being: good conductors of electricity, malleable, and ductile.
- Electrons can move freely which allows the metal to be a good conductor of electric current.
- Metals are ductile and malleable because of the mobility of the valance electrons.

Crystalline Structure of Metals
- Metals are crystalline and are arranged in regular and compact patterns.
- There are three arrangements of crystalline metals: Hexagonal close packed structure, body-centered cubic structure, and face-centered cubic structure.
- The body-centered cubic unit cell has atoms at each of the eight corners of a cube plus one atom in the center of the cube. Each of the corner atoms is the corner of another cube so the corner atoms are shared among eight unit cells.
- In the face centered cubic structure, each of the corner atoms is the corner of another cube so the corner atoms are shared among eight unit cells. Additionally, each of its six face centered atoms is shared with an adjacent atom. Since 12 of its atoms are shared, it is said to have a coordination number of 12.
- The hexagonal structure of alternating layers is shifted so its atoms are aligned to the gaps of the preceding layer. The atoms from one layer nest themselves in the empty space between the atoms of the adjacent layer just like in .

- An alloy is a partial or complete solid solution of one or more elements in a metallic matrix.
- Alloying one metal with other metals or non-metals often enhances its properties. For example, steel is stronger than iron, its primary element.
- Steel is a very important alloy

Group 2: Pages 213-236

Coeditor: Shannon Degnan

Pages 213-215: molecules/molecular compounds and molecular formulas by Alex Fischbach

Molecules and Molecular Compounds
- Noble gases consist of single atoms
- Monatomic: consisting of single atoms
- Covalent bond: atoms are held together by sharing electrons, resembles a “tug of war” between the electrons
- Many elements are formed in molecules
- Molecule: a natural group of atoms joined together by covalent bonds.
- Diatomic molecules: a molecule consisting of two atoms
- In many compounds atoms are bonded together to form molecules
- Molecular Compound: a compound composed of molecules. All the molecules are the same
- Molecular compounds tend to have relatively lower melting and boiling points than other ionic compounds
- Many are gases or liquids are room temperature
- Ionic compounds: formed by a metal combined with a nonmetal
- Molecular compounds are composed of atoms of two or more nonmetals
Molecular Formulas
- Molecular formula: is the chemical formula of a molecular compound
- A molecular formula shows how many atoms of each element a molecule contains
- Subscript after the symbol indicated the number of atoms of each element in the molecule
- If there is only one atom, the subscript 1 is omitted
- A molecular formula reflects the actual number of atoms in each molecule
- Subscripts are not always whole numbers
- They also describe molecules consisting of one element
- It does not tell you about structure (the arrangement of atoms)
By: Alexandra Fischbach "Covalent bonds" ^

Learn how to name and make covalent bonds:

Pages 217-220: octet rule in covalent bonding and single covalent bonds by Meghan Faber

The Octet Rule in Covalent Bonding:
  • in the formation covalent bonds, electron sharing usually occurs so atoms have the electron configuration of noble gases.
  • Ex: Hydrogen: each atom has one electron. When two hydrogen atoms form a covalent bond- they share the two electrons, therefore having the electron configuration of Helium. (noble gas with two electrons)

Single Covalent Bonds
  • Atoms in a molecule are held together mainly by the attraction between the shared electrons (negative) and and the nuclei (which is positive)
  • A Single Covalent bond is formed when two atoms are held together by a shared pair of electrons.
  • An electron dot structure represents the shared pair of electrons of the covalent bonds by two dots. Ex: H:H
  • Structural formula: represents the covalent bonds by dashes and shows the arrangement of covalently bonded atoms.
  • Halogens form single covalent bonds in their diatomic molecules.
  • Unshared pair: pair of valence electrons not shared between atoms.
  • Electron dot structures are drawn similarly to molecules of diatomic elements.
  • You can predict the amount of bonds based on the electron configuration.
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Pages 221-223: double/triple covalent bonds and coordinate covalent bonds by Colleen Fitzgerald

Double and Triple Covalent Bonds
  • Atoms form double or triple covalent bonds if they can attain a noble gas structure by sharing two or three pairs of electrons
  • A bond that involves two shared pairs of electrons is a double covalent bond
  • A bond formed by sharing three pairs of electrons is a triple covalent bond

Coordinate Covalent Bond
  • A coordinate covalent bond is a covalent bond in which one atom contributes both bonding electrons
  • A coordinate covalent bond is represented in a structural formula by an arrow that starts at the atom giving away the electron and ends at the atom recieving them
  • A polyatomic ion is a tightly bound group of atoms that have a positive or negative charge and behave as a unit.
external image coord.jpgCoordinate Covalent Bond-Colleen Fitzgerald http://www.chemistry.wustl.edu/~edudev/LabTutorials/Hemoglobin/images/coord.jpg

Pages 226-229: bond dissociation energies and resonance and exceptions to the octet rule by Grayce Rose

Pages 230-236: molecular orbitals and VSEPR theory and hybrid orbitals by Shannon Degnan

Group 3: Pages 237-266

Coeditor: Brendan Lynch

Pages 237-244: polar bonds and molecules by Brendan Lynch

Bond Polarity

-Covalent bonds involve electron sharing between atoms. Bonds differ in how the bonded atoms share electrons. The electrons in covalent bonds are pulled by the nuclei of the two atoms, like a game of tug-of-war.
-When the atoms in the bond pull equally ( like when the same atoms are bonding), the bond is called a non-polar covalent bond.
-A polar bond is a covalent bond in which the electrons are shared unequally.
-The more electronegative atom attracts electrons more strongly, gaining a slightly negative charge.
-The less electronegative atom has a slightly positive charge.
-The higher the electronegativity value, the greater the ability of an atom to attract electrons to itself.
Polar Molecules
The presence of a polar bond in a molecule often makes the entire molecule polar. In a polar molecule, one end of the molecule is slightly negative and the other is slightly positive.
Attraction between molecule
Intermolecule attractions are weaker than either ionic or covalent bonds.
Van der Waals forces are the two weakest type of molecular attractions.
Dipole interactions occur when polar molecules are attracted to one another.
Dispersion forces are caused by the motion of electrons.
Hydrogen bond are attractive forces in which hydrogen covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom.
Network solids are solids in which all the atoms are covalently bonded to each other. ex. Diamonds.
external image water.gif( by Brendan Lynch http://www.biology.arizona.edu/biochemistry/tutorials/chemistry/page3.html)

Learn about electronegativity:

Pages 253-255: monatomic ions by Kelsey Sullivan

Monatomic Ions

  • Monatomic Ions
    • Ions that consist of a single atom with a positiv or negative charge resulting from the loss or gin of one o more valence electrons
  • Cations
    • Metallic elements tend to lose valence electrons
    • Elements in group 1A lose ne electron to form cations
    • When elements in groups 1A, 2A, and 3A lose electrons,they form cations with positive charges equal to their group number
  • Anions
    • Nonmetals gain electrons to form anions, so the charge is negative
    • The charge of any ion of a Group A nonmetal is determined by subtracting 8 from the group number
  • Ions of Transition Metals
    • Transition metals form more than one cation with different ionic charges
    • two methods used to name these ions
      • Stock system
        • In this system, you put a roman numeral after the element name to indicate the numerical value of the charge
      • The second way:
        • uses a root word with different suffixes at the end of the word
    • A few transition metals ave only on ionic charge
    • The names of these cations do not ahve a roman numeral

Pages 257-258: polyatomic ions by Lindsey Bedrosian

Monatomic Ions
-Ionic compounds consist of a positive metal ion and a negative nonmetal ion combined in a proportion such that their charges add up to a net change of zero
-monatomic ions consist of a single atom with a positive or negative charge resulting from the loss or gain of one or more valence electrons
-When metals in groups 1A, 2A, and 3A lose elections they form cations with positive charges equal to their group number.

Anions -Formed when nonmetals gain electrons so the chrge of the nonmetallic ion is negative -The names of anions start with the stem of the element name and end in -ide.

Ions of Transition Metals -Many transition metals form more then one cation with different ionic charges. -Charges of the cations of many transition metal ions must be determinedfrom the number of electrons lost. -The stock system and the root name are ways to name cations

Transition Metals With Only One Charge
-Silver,Cadmium, and zinc
-Elements contain very colorful pigments

external image monoatomic_ions_Silberberg_table_2.3.jpg
Cations and Anions by Lindsey Bedrosian

Pages 260-263: binary ionic compounds by Kim Kogut
Naming Binary Ionic Compounds~
-A binary compound is a compound composed of two elements and can be either ionic or molecular.
-A shorthand way of writing binary compounds is to use formulas.
-If you know the formula for a compound, then you can identitfy its name.
-To name any binary compound, place the cation name first, followed by the anion name.
-Pay attention to the subscripts of the elements in the compound. These can imply charges, which can differ from time to time.
By: Kim Kogut http://www.files.chem.vt.edu/RVGS/ACT/notes/Nomenclature.html

Writing Formulas for Binary Ionic Compounds~
-As the same with naming formulas, you can write a compound's formula if you have the name.
-Write the symbol of the cation and then the anion. Add whatever subscripts are needed to balance the charges.
-Again, keep in mind how many ions each element of the compound has. Refer to a periodic table if you aren't sure.
-A handy way of writing balanced formulas is to use the criss-cross method.
-In this system, you switch around the charge numbers of the compound. It then becomes the subscript of the opposite element. The formula should then be correct because the charges should cancel out to zero, making the formula balanced.
-Remember to use whole number ratios.
By: Kim Kogut http://www.files.chem.vt.edu/RVGS/ACT/notes/Nomenclature.html

By: Kim Kogut http://www.youtube.com/watch?v=7Lfc6jjp1WQ&feature=channel

Pages 264-266: compounds with polyatomic ions by Abby John

Compounds with Polyatomic Ions
-An –ate or –ite ending on the name of the compound indicates that the compound contains a polyatomic anion that contains oxygen
-in the formula the charge is balanced(equal) and the ions are in the lowest possible whole number ratio
Naming compounds -first, recognize that the compound contains a polyatomic ion -to name a compound containing a polyatomic ion, write the cation first and then the anion

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polyatomic compounds by Abby John

Group 4: Pages 268-278

Coeditor: Julia McNamara

Pages 268-269: naming binary molecular compounds by Anne O'Toole
  • A binary compound cannot contain more than two elements
  • -ate and -ite ending on the name of a compound indicateds that the compound contains a polyatomic anion that includes oxygen

Pages 270-272: writing formulas for binary molecular compounds by David O'Brien

Writing Formulas for Binary Molecular Compounds
- use prefixes in the compound name to tell you the subscript
- then write the symbols for both elements and include their subscripts
- ex.) Silicon Carbide (no prefixes) = SiC
- ex.) Dinitrogen Tetraoxide (Di=2 & Tetra=4) = N2O4

Naming Acids
- Acid = a compound that contains one or more hydrogen atoms
- acid can consist of a anion and as many hydrogen ions needed to make the molecule electrically neutral
- Typical formula) HnX
1. X is a monatomis or polytomic anion
2. N us a subscript (# of hydrogen ions combined with the anion)
- 3 Rules for naming acids
1. When the name of the anion(X) ends in –ide, the acid name begins with hydro-. The stem of the anion has the suffix –ic and is followed by the word acid.
§ Ex.) HCl(aq) (X= chloride) = hydrochloric acid
2. When the anion name ends in –ite, the acid name is the stem of the anion with the suffix –ous, followed by the word acid.
§ Ex.) H2SO3(aq) (X=nitrate) = sulfurous acid
3. When the anion names ends in –ate, the acid name is the stem of the anion with the suffix –ic followed by the word acid.
§ HNO3(aq) (X=nitrate) = nitric acid

Writing Formulas for Acids
- Use the rules above in reverse to write formulas when you know the name of an acid.

- Ex.) hydrobromic acid (hydro- prefix & -ic suffix) = HBr
By: David O'Brien

Pages 272-273: writing formulas for acids and names/formulas for bases by Marybeth Nametz

Naming Acids
Three Rules can help you name an acid with the general formula HnX
  1. When the name of the anion (X) ends in -ide, the acid name begins with the prefix hydro-. The stem of the anion has the suffix -ic and is followed by the word acid.
  2. When the anion name ends in -ite, the acid name is the stem of the anion with the suffix -ous, followed by the word acid.
  3. When the anion name ends in -ate, the acid name is the stem of the anion wiht the suffix -ic followed by the word acid.

Writing Formulas for Acids
If you know the name of an acid, you can write its formula...
  • Use the rules for writing the names of acids in reverse to write the formulas for acids
    ( ex. Hydrobromic acid. Recall- Rule 1. [hydro- prefix and -ic suffx] this must be a combination of hydrogen ion (H+) and bromide ion (Br-). The formula then for Hydrobromic acid is HBr)

Names and Formulas for Bases
Another group of ionic compounds is the bases... (Base: an ionic compound that produces hydroxide ions when dissolved in water)
  • Bases are named in the same way as other ionic compounds-- the name of the cation is followed by the name of the anion
(ex. Sodium hydroxide [NaOH] is a base. To write the formulas for bases, write the symbol for the metal cation followed by the forumula for the hydroxide ion. Balance the ionic charges just as you do for any ionic compound.)
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(By Marybeth Nametz http://library.tedankara.k12.tr/chemistry/vol4/Introduction/h7.htm)

Pages 274-275: the laws of definite and multiple proportions by Julia McNamara

Pages 276-278: practicing skills- naming chemical compounds by Emily Taylor

- 2 basic skills you've learned to help you deal with an emergency involving chemicals:
- Naming Chemical Compounds
- Writing Chemical Formulas
- The flowchart below helps you to name a compound is you know that its a formula.
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Naming Chemical Compounds Flowchart - Emily Taylor http://www.pspcisd.net/Faculty/Wood/FWschoolweb/chem_notes_5.htm

- An -ide ending generally indicates a binary compound.
- An -ite or -ate ending mean a polyatomic ion that includes oxygen in the formula.
- Prefixes in a name generally indicate that the compound is molecular.
- A Roman numeral after the name of a cation (+) shows the ionic charge of the cation.
- The flowchart below helps you write chemical formulas if you know the compound name.
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Writing Chemical Formulas Flowchart - Emily Taylor http://www.pspcisd.net/Faculty/Wood/FWschoolweb/chem_notes_5.htm