Chemistry Matter and Change - Chapter 7

DeRosa Chem A

Chemical bond

like glue/the force that holds two atoms together. Can form by the attraction between positive ions and negative ions and the positive nucleus and negative electrons

Cations

a positively charged ion; most common are those produced by loss of valence electrons from metal atoms

Anion

a negatively charged ion; end in -ide; gained by neutral atom

Ionic bonding

the electrostatic forces that hold oppositely charged particles together; made of cations and anions; they are electrically neutral

Ionic Compounds

salts, compounds that contain ionic bonds; physical structures are unique, large number of +ions and -ions exist in a ratio determined by the number of electrons transferred from a metal atom to a non-metal atom; packed into a regular repeating pattern, balances forces of attraction and repulsion between ions;

Crystal lattice

a three-dimensional geometric arrangement of particles

Electrolytes

an ionic compound whose water solution conducts an electric current

Lattice energy

the energy required to separate 1 mol of the ions of an ionic compound (energy needed to break up electrolyte);the greater the charge of the ions the greater the lattice energy is; the smaller the size of the ion, the more lattice energy

Formula unit

Chemical formula that represents the simplest ratio of ions involved

Monatomic ion

a one-atom ion, such as Mg²⁺ or Br⁻

Oxidation number

the charge of a monatomic ion.

Polyatomic ions

ions made up of more than one atom that are bonded together that acts as a single unit with a net charge. (ex. Nitrate= NO₃⁻) End in -ite, -ate

Oxyanions

a polyatomic ion composed of an element, usually a nonmetal, bonded to one or more oxygen atoms.

Ionic crystal

hard ridged brittle solids, due to strong attractive forces holding ions in place at room temp (Mohs scale); crystal breaks apart because applied force repositions the like-charged ions next to each other

properties of ionic compound

solid, hard, brittle, high melting/boiling points, can conduct eletricity when melted or desolved in water, well-designed crystals at room temp

valence electrons

the electrons in the highest occupied energy level of the elements atom, farthest from the nucleus. The number of valence electrons determines the chemical properties of the element; they are grouped together on the periodic table (ex. group 1 have 1 valence electron, group 4 have 4 valence el); they are the only electrons used in a chemical bond; dots in dot structure

Dot structure

Lewis, how many electrons in the valence shell (most outer energy level)

formula unit/ ratio

lowest whole-number ratio of ions in an ionic compound. NaCL = 1:1

pseudo-noble gas configuration

electron configurations other than the octet rule that give some stability, for example groups 11-14 may have full s, p, d sublevels

-ide

ending of an anion

properties of ionic compounds

strong attraction between oppositely charged ions means:high melting & boiling pointsionic crystals are very hard but brittleconduct electricity when dissolved in solution or melted (ELECTROLYTES)

Electrolyte

substance that forms ion when it is dissolved in water, capable of conducting an electrical current

What is the compound of Al and S

Al₂S₃

Name MgO

Magnesium Oxide

metallic bond

The electrostatic attraction between cations and the negatively charged sea of electrons.

delocalized electrons

these electrons do not orbit any particular atom, but constantly move among different atoms-this creates a "sea" of electrons throughout the metal

electron sea model

simplest picture model. pictures a regular array of metal atoms in a "sea" of valence electrons that are shared among the atoms in a nondirectional way

properties of metallic bonds

mealable, ductile

aluminum

will always have a +3

silver

will always be +1

zinc

will always be +2

Acetate ion

C₂H₃O₂⁻

Carbonate ion

CO₃⁻²

Sulfate ion

SO₄⁻²

Phosphate ion

PO₄⁻³

Nitrate

NO₃⁻

amonium ion

NH₄⁺

Hydroxide

OH⁻

Cyanide ion

CN⁻

\____ alloys are formed when some atoms in the original metallic solid are replaced by other metals of similar atomic structure.

substitutional

\____ alloys are formed when small holes in a metallic crystal are filled with smaller atoms.

interstitial

An \____ is a mixture of elements that has metallic properties. (mixture not compound which allows for different strengths)

alloy

The properties of alloys \____ from the elements they contain

differ

\____ electrons around cations make metals \_____ conductors of electricity and heat.

Mobile, good

As the number of delocalized electrons \_____, so does hardness and strength.

increases

Metals are \____ because they can be hammered into sheets.

malleable

Metals are \_____ because they can be drawn into wires.

ductile

Boiling points are much \_____ extreme than melting points because of the energy required to \_____ atoms from the groups of cations and electrons.

more, separate

A \______ is the attraction of a metallic cation for delocalized electrons.

metallic bond

Within the crowded lattice, the outer energy levels of metal atoms \_____.

overlap

The electron sea model proposes that all \______________________ contribute their valence electrons to form a "sea" of electrons.
The electrons are free to move around and are referred to as \_____ electrons, forming a metallic cation.

metal atoms in a metallic solid
delocalized

Metals are not ionic but \___________________________.

share several properties with ionic compounds.

Metals also form lattices in the \________, where 8 to 12 other atoms \__________________________.

solid state, closely surround each metal atom.

Chemical \_____ is a systematic way of naming compounds.

nomenclature

An \_______ is a polyatomic ion composed of an element (usually a non-metal), bonded to \_________.

oxyanion, bonded to one or more oxygen atoms.