chemistry chapter 6

The fact that metals are malleable and ionic crystals are brittle is best explained in terms their

chemical bonds

A ____ is a shorthand representation of the composition of a substance using atomic symbols and numerical subscripts.

chemical formula

The bonds within polyatomic ions are predominantly

covalent

In the formation of a covalent bond, as the distance between two atoms begins to decrease, the potential energy

decreases (Lower potential energy, greater stability)

The equal but opposite charges present in two regions of a polar molecule create a

dipole

The property of metallic luster is most closely related to the metal's

electron sea

VSPER is based on the assumption that

electrons in the molecules repel each other

In the formula for sodium chloride, NaCl stands for one

formula unit

In orbital notation, the hybridized orbitals responsible for

high electronegativity

brittle(metallic solid or ionic solid)

ionic

nonconductive(metallic solid or ionic solid)

ionic

The difference in electronegativity and the type of bond for the Li-Cl (electronegativity for Li=1.0 ; for Cl=3.0) is

ionic 2.0

Compared to the neutral atoms involved in its formation, the crystal lattice that results is

lower in potential energy

Metals are referred to as _________ which means shiny

lustrous

lustrous(metallic solid or ionic solid)

lustrous

The property called _____ is the ability to be shaped or extended by physical pressure.

malleability

malleable(metallic solid or ionic solid)

malleable

A ______ bond is a type of chemical bond that results from the attraction between positive ions and surrounding mobile electrons.

metallic

ductile (metallic solid or ionic solid)

metallic

In the NaCl crystal, the packing of Na+ ions and Cl- ions in a crystal is the state of ______ ________ energy

minimum (or lowest) potential

What can VSEPR theory be used to predict

molecular geometry (shapes of molecules)

When an atom of one element combines chemically with an atom of another element, both atoms usually attain the stable highest-energy-level configuration of a

noble gas

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

non polar covalent

How many double bonds are in the Lewis structure for hydrogen fluoride, which contains one hydrogen atom and one fluorine atom?

none

To draw the electron-dot symbols for each atom in a Lewis structure one must know the

number of valence electrons

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

polar

If the electrons involved in bonding spend most of the time close to one atom rather than the other, the bond is

polar

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

polar covalent

in molecules, unshared electron pairs tend to

repel electrons more strongly than bonding electron -pairs

The chemical formula for an ionic compound represents the

simplest ration of the combined ions that gives neutrality

Compared to nonmetals, the number of valence electrons in metals tends to be

smaller

At room temperature, most ionic compounds will be

solids

The structural formula for water, and describe its shape

H-O ' bent H

List the diatomic molecules in order of increasing atomic #

H2, N2, O2, F2, Cl2, Br2, I2

In which of these compounds is the bond between the atoms NOT a non polar covalent bond?

HCl

Compared to ionic compounds, molecular compounds

Have lower melting points

The difference in electronegativity and the type of bond for the Br-Br bond in Br2 (electronegativity for Br=2.8) is

0% non polar covalent

In s-block and d-block metals, the number of valence electrons in the outermost s sub level is usually

1 or 2

The key to understanding why atoms bond is that they go to states of lower ________ and greater _______

1. potential energy 2. stability

When Sodium (electron configuration 1s2 2s2 2p6 3s1) combines with chlorine to form sodium chloride, the sodium attains the electron configuration

1s2 2s2 2p6

The phosphate ion, PO3- has how many extra electrons 4

3

In a molecule of fluorine, the two shared electrons give each fluorine atom ______ electrons in the outer energy level.

8

________ is the property of being able to be drawn into a wire.

Ductility

A chemical bond resulting from electrostatic attraction between positive and negative ions is called an

Ionic bond

The greater the electronegativity difference between two bonded atoms, the greater the percentage of

Ionic character

The lattice energy of compound A is greater than that of compound B. What can be deduced from this fact?

It will be more difficult to break the bonds in compound A than in compound B.

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

Lattice

The only intermolecular forces acting among atoms of noble gases and among non polar molecules are

London forces

Of the following molecules, all of which contain polar bonds, the only polar molecule is

NH3

The substance whose Lewis structure indicates three covalent bonds is

NH3

In a chemical bond, the link between atoms results from the attraction between electrons and

Nuclei

In metals, the valence electrons are considered to be

Shared by all of the atoms

Which of the following is NOT a property of an ionic compound?

Vaporizes readily at room temperature.

Water and CO2 are both triatomic molecules. Explain why one is polar and the other is non polar.

Water is polar bc it is asymmetric. CO2 is non polar bc it is symmetric.

A polar molecule (no ions) is one in which

a region of positive charge and a region of negative charge exist

A covalent bond consists of

a shared electron pair

the structure of the methane molecule (CH4) is described as

a tetrahedral

In a crystal of an ionic compound, each cation is surrounded by a number of

anions

Dipole-Dipole forces are considered the most important forces in polar substances because the London dispersion forces

are usually much weaker than the dipole-dipole forces

A non polar covalent bond is likely to exist between

two identical atoms

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

valence electrons

Water and CO2 are both triatomic molecules. Explain why one is polar and the other is non polar.

water is polar because it is asymmetric. CO2 is nonpolar because it is symmetric

The forces of attraction between molecules in a molecular compound are

weaker than the forces of ionic bonding.