Chemistry Chapter 6 Review

Polyatomic Ions

a charged group of covalently bonded atoms. Here is a Quizlet deck of some common ones: "http://quizlet.com/31357022/polyatomic-ions-flash-cards/".

Molecular Compound

a chemical compound whose simplest units are molecules

Single Bond

a covalent bond in which one pair of electrons is shared between two atoms

Polar-Covalent Bond

a covalent bond in which the bonded atoms have an unequal attraction for the shared electrons. Electronegativity difference of about 0.3-1.7.

Nonpolar-Covalent Bond

a covalent bond in which the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge. Electronegativity difference of about 0-0.3.

Triple Bond

a covalent bond in which three pairs of electrons are shared between two atoms.

Double Bond

a covalent bond in which two pairs of electrons are shared between two atoms.

Diatomic Molecule

a molecule containing only two atoms.

Molecule

a neutral group of atoms that are held together by covalent bonds.

A covalent bond consists of

a shared electron pair

Chemical Bond

mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together.

Is H-H nonpolar covalent, polar covalent, or ionic?

nonpolar covalent

if two covalently bonded atoms are identical, the bond is identified as

nonpolar covalent

A chemical bond between atoms results from the attraction between the valence electrons and _______ of different atoms

nuclei

Hybrid Orbitals

orbitals of equal energy produced by the combination of two or more orbitals in the same atom.

A covalent bond is which there is an unequal attraction for the shared electrons is

polar

Is CH2O polar or nonpolar?

polar

Is COCl2 polar or nonpolar?

polar

Is H2S polar or nonpolar?

polar

Is PCl3 polar or nonpolar?

polar

Bonds that possess between 5% and 50% ionic character are considered to be

polar covalent

Is H-C nonpolar covalent, polar covalent, or ionic?

polar covalent

Is H-N nonpolar covalent, polar covalent, or ionic?

polar covalent

Is H-O nonpolar covalent, polar covalent, or ionic?

polar covalent

if electrons involved in bonding spend most of the time closer to one Adam rather than the other, the bond is

polar covalent

What to Know for the Final From This Chapter

- Decide if a bond is ionic, polar covalent, or nonpolar covalent based on electronegativity difference - Draw Lewis structures for different compounds. - Be able to predict molecule shape using VSEPR theory - Vocabulary

A bond characters more than 50% ionic of the electronegativity difference between the two atoms is greater then

1.7

How is a hydrogen bond different from an ionic or covalent bond?

A hydrogen bond is a dipole - dipole attraction between a partially positive hydrogen atom and the unshared electron pair of a strongly electronegative atom such as O, N, or F. Unlike ionic or covalent bonds, in which electrons are given up or shared, the hydrogen bond is a weaker attraction. Hydrogen bonds are generally intermolecular, which ionic and covalent bonds occur between ions or atoms respectively.

Describe how I covalent bond holds two atoms together

A pair of electrons is attracted to both nuclei of the two atoms bonded together

Use the concept of potential energy to describe how a covalent bond forms between two atoms

As the atoms involved in the formation of a covalent bond approach each other, the electron-proton attraction is stronger than the electron-electron and proton-proton repulsions. The atoms are drawn to each other and their potential energy decreases. Eventually, a distance reached at which the repulsion has the like charges equals the attraction of the opposite charges. At this point, potential energy is at a minimum and a stable molecular form.

What two factors determine whether or not a molecule is polar?

Electronegativity difference in molecular geometry or unshared electron pairs.

Nonpolar covalent compound example

H2

Polar covalent compound example

HCl

Name two elements that form compounds that can be exceptions to the octet rule

Hydrogen, Boron, Beryllium, Phosphorous, Sulfur, and Xenon

Chart for VSEPR Theory

Linear: AB₂ Trigonal-planar: AB₃ Bent/Angular: AB₂E Tetrahedral: AB₄ Trigonal-pyramidal: AB₃E Bet/Angular: AB₂E₂ Trigonal-bipyramidal: AB₅ Octahedral: AB₆

Ionic compound example

NaCl

H2S and H20 have similar structures and their central Adams belong to the same group. Yet H2S is a gas at room temperature and H2O is a liquid. Use bonding principles to explain why this is

Oxygen has higher electronegativity than sulfur, which creates a highly polar bond. Increase polarity in H2O bonds means a stronger intermolecular attraction making water a liquid at room temperature. Hydrogen bonding exists between water molecules, but not between hydrogen sulfide molecules.

Identify the major assumption of the VS EPR theory, which is used to predict the shape of atoms.

Pairs of valence electrons repel one another

Explain why resonance structures are used instead of Lewis structures to correctly model certain molecules

Resonance structures show that one Lewis structure cannot correctly represent the location of the electrons in a bond. Resident structures show delocalized electrons, while Lewis structures depict electrons in a definite location.

How can electronegativity be used to distinguish between an ionic bond in a covalent bond?

The difference between the electronegativity of the two atoms in a bond will determine whether the bond is ionic or covalent. If the difference in electronegativity is greater than 1.7, the bond is considered ionic.

In water, two hydrogen atoms are bonded to one oxygen atom. Why isn't water a linear molecule?

The electron pairs that are not involved in bonding also take up space, creating a tetrahedron of electron pairs and making water molecule angular or bent.

Describe the electron distribution in a polar-covalent bond and it's effects on the partial charges of the compound

The electrons density is greater around the more electronegative atom, giving that part of the compound a partial negative charge. The other part of the compound has an equal partial positive charge.

What orbitals combine together to form sp3 hybrid orbitals around a carbon atom?

The s orbital and all three p orbitals from the second electron energy level

In what way is a polar-covalent bond similar to an ionic bond?

There's a difference between the electronegativity of the two atoms in both types of bonds that results in electrons being more closely associated with the more electronegative atom

How are dipole - dipole attractions, London dispersion forces, and hydrogen bonding similar?

They're all forces of attraction between molecules. In all cases there is an attraction between the slightly negatively charged portion of one molecule in the slightly positively charged portion of another molecule.

Electron-Dot Notation

an electron-configuration notation in which only the valence electrons of an atom of a particular element are shown, indicated by dots placed around the element's symbol.

Resonance

bonding in molecules or ions that cannot be correctly represented by a single Lewis structure.

Polar

bonds that have an uneven distribution of charge.

Metallic Bonding

chemical bonding that results from the attraction between metal atoms and the surrounding sea of electrons.

Ionic Bonding

chemical bonding that results from the electrical attraction between cations and anions.

Octet Rule

chemical compounds tend to form so that each atom, by gaining, losing, or sharing electrons, has an octet of electrons (8) in its highest occupied energy level.

Ionic Compound

composed of positive and negative ions that are combined so that the numbers of positive and negative charges are equal. Most of these exist as crystalline solids.

Dipole

created by equal but opposite charges that are separated by a short distance.

Multiple Bonds

double and triple bonds.

What property of the two atoms is in a covalent bond determines whether or not the bond will be polar?

electronegativity

Intermolecular Forces

forces of attraction between molecules.

Lewis Structures

formulas in which atomic symbols represent nuclei and inner-shell electrons, dot-pairs or dashes between two atomic symbols represent electron pairs in covalent bonds, and dots adjacent to only one atomic symbol represent unshared electrons.

Atoms with a strong attraction for the electrons they share with another atom exhibit

high electronegativity

Structural Formula

indicates the kind, number, arrangement, and bonds but not the unshared pairs of the atoms in a molecule.

Chemical Formula

indicates the relative numbers of atoms of each kind in a chemical compound by using atomic symbols and numerical subscripts.

Is H-F nonpolar covalent, polar covalent, or ionic?

ionic

Is Na-Cl nonpolar covalent, polar covalent, or ionic?

ionic

Chemical bond that results from the electrostatic attraction between positive and negative ions is called a

ionic bond

if a bond characters more than 50% ionic, than the bond is called a

ionic bond

The greater the electronegativity difference between two Adams bonded together, the greater the bonds percentage of

ionic character

VSEPR Theory

repulsion between the sets of valence-level electrons surrounding an atom causes these sets to be oriented as far as possible. To use the chart, know that A stands for the center and is always there, B is the number of bonds from the central atom, and E is any lone pair of electrons. For B and E, the subscripts represent how many of each there are (# of bonds, # of lone pairs) in the particular molecule.

Covalent Bonding

results from the sharing of electron pairs between two atoms.

Molecular Formula

shows the types and numbers of atoms combined in a single molecule of a molecular compound.

Ductility

the ability of a substance to be drawn, pulled, or extruded through a small opening to produce a wire.

Malleability

the ability of a substance to be hammered or beaten into thin sheets.

Bond Length

the average distance between two bonded atoms

Lattice Energy

the energy released when one mole of an ionic crystalline compound is formed from gaseous ions.

Bond Energy

the energy required to break a chemical bond and form neutral isolated atoms.

London Dispersion Forces

the intermolecular attractions resulting from the constant motion of electrons and the creation of instantaneous dipoles.

Hydrogen Bonding

the intermolecular force in which a hydrogen atom that is bonded to a highly electronegative atom is attracted to an unshared pair of electrons of an electronegative atom in a nearby molecule.

Hybridization

the mixing of two or more atomic orbitals of similar energies on the same atom to produce new hybrid atomic orbitals of equal energies.

Formula Unit

the simplest collection of atoms from which an ionic compound's formula can be established.

Molecular Polarity

the uneven distribution of molecular charge.

The electrons involved in the formation of a chemical bond are called

valence electrons