Mcat General Chemistry Terms And Concepts

Front 1

acid

Back 1

a compound that produces hydronium ion (simplified as H+) in water solution

Front 2

acid-base reaction

Back 2

a reaction in which an acid reacts with a base and forms an ionic compound and water

Front 3

acidic salt

Back 3

the measure of the concentration of hydronium ion in a dilute aqueous solution

Front 4

alkali metals

Back 4

the metals of group IA

Front 5

alkaline earth metals

Back 5

the metals of group IIA

Front 6

anion

Back 6

a negatively charged ion

Front 7

angular momentum quantum number (I)

Back 7

the quantum number the describes the three-dimensional shape of an orbital; it is all integer values from 0 up to n-1

Front 8

arrhenius equation

Back 8

an equation that allows the calculation of the activation energy of a reaction given the rate constants at two different temperatures

Front 9

atom

Back 9

the smallest particle of a substance, made up of a nucleus surrounded by an electron cloud

Front 10

atomic number (Z)

Back 10

the number assigned to an atom on the periodic table that is equivalent to the number of protons in the nucleus of that atom

Front 11

atomic radius

Back 11

the radius of an atom, found by dividing by 2 the distance between two nuclei in a diatomic molecule

Front 12

atmospheric pressure (atm)

Back 12

the force exerted by the gases of the atmosphere onto the surface of the Earth due to gravity

Front 13

autoionization

Back 13

the dissociation that water undergoes into hydronium ions and hydroxide ions, with Kw equal to 1.0*10^-14 at 25 degrees celsius

Front 14

avogadro's law

Back 14

states: "a mole of any gas occupies the same volume at a given temperature and pressure."

Front 15

balanced chemical equation

Back 15

chemical equation that has the same number of each type of atom on both sides of the equation

Front 16

balmer series

Back 16

the series of lines seen in the visible part of the emission spectrum of the hydrogen atom. it consists of four lines that arise from the 6 to 2, the 5 to 2, the 4 to 2, and the 3 to 2 transitions.

Front 17

barometer

Back 17

instrument used to measure atmospheric pressure

Front 18

base

Back 18

compound that produces hydroxide ion in aqueous solution

Front 19

basic salt

Back 19

ionic compound that is the product of a strong base and a weak acid, and has a basic pH in aqueous solution

Front 20

boiling point elevation

Back 20

a colligative property of solutions that increases the boiling point of a solvent due to the presence of solute particles

Front 21

boyle's law

Back 21

states: the pressure of a gas is inversely related to its volume at constant temperature

Front 22

buffer

Back 22

a solution that resists change in pH on small additions of acid or base

Front 23

calorie

Back 23

a unit of heat energy that is equivalent to 4.184 J.

Front 24

calorimetry

Back 24

a procedure that uses a calorimeter to measure the heat changes that occur within a system

Front 25

catalyst

Back 25

a substance that speeds a reaction rate by lowering the activation energy of the reaction; it is recovered at the end of the reaction

Front 26

cathode

Back 26

the electrode in an electrochemical cell where reduction takes place

Front 27

cation

Back 27

a positively charged ion

Front 28

cell notation

Back 28

a shorthand method for drawing a voltaic cell

Front 29

cell voltage (Ecell)

Back 29

the voltage generated by an electrochemical cell; it can also be called electromotive force (emf) or cell potential

Front 30

charle's law

Back 30

states: the volume of a gas is directly related to temperature at constant pressure

Front 31

chemical formula

Back 31

the representation of the fundamental unit of a substance that uses symbols and subscripts to state the elements present and their molar ratio

Front 32

coefficient

Back 32

the number found in front of a formula in a balanced chemical equation that represents the mole quantity of that substance in the balanced equation

Front 33

colligative properties

Back 33

properties of solutions that result in a change in the boiling point, the melting point, and the vapor pressure of a solvent due to the presence of solute particles

Front 34

colloid

Back 34

consists of small particles suspended in a medium

Front 35

combination reaction

Back 35

an oxidation-reduction where two substances combine into one substance

Front 36

combustion reaction

Back 36

an oxidation-reduction reaction that occurs when a substance is burned in oxygen and produces one or more oxides

Front 37

common ion effect

Back 37

the effect on the solubility reaction that occurs when a substance is burned in oxygen and produces one or more oxides

Front 38

covalent compound

Back 38

a compound that is made of atoms held together by covalent bonds; the formula has nonmetals as its elements

Front 39

critical point

Back 39

the point on a pressure-temperature phase diagram that marks the end of the liquid-gas boundary line; at all temperatures and pressures beyond this point, the substance exists in the supercritical fluid phase

Front 40

dalton's law

Back 40

in a mixture of gases, each gas exerts it's own partial pressure that is directly related to the mole fraction of the gas in the mixture

Front 41

decomposition reaction

Back 41

an oxidation-reduction reaction where a single substance decomposes into two or more substances

Front 42

dipole

Back 42

a covalent bond that has a partially negative end at the more electronegative atom, and a partially positive end at the less electronegative atom

Front 43

dipole-dipole interactions

Back 43

the intermolecular force found in liquid or solid samples of covalent molecules that contain a polar bond

Front 44

dipole moment

Back 44

a number that is the measure of the polarity of a covalent bond

Front 45

dispersion forces

Back 45

the intermolecular force found in liquid or solid samples of covalent molecules that contain nonpolar bonds

Front 46

effective nuclear charge

Back 46

the number of protons in the nucleus less the shielding effect of the innermost electrons

Front 47

electrochemistry

Back 47

the study of oxidation-reduction reactions that can be used either to generate electricity or that require electricity to proceed

Front 48

electrolytic cell

Back 48

an electrochemical cell that requires electricity to run a nonspontaneous oxidation-reduction reaction

Front 49

electron

Back 49

the negatively charged particle with negligible mass that is found in a cloud surrounding the nucleus of an atom

Front 50

electron affinity

Back 50

the energy change that occurs when an electron is added to a valence orbital, producing an anion

Front 51

electron configuration

Back 51

lists the orbitals in order of their energies and gives the number of electrons in each orbital as a superscript

Front 52

electronegativity

Back 52

the ability of an atom in a molecule to pull the electron density of a covalent bond toward itself

Front 53

empirical formula

Back 53

the chemical formula of a substance that shows the lowest whole-number ration of the elements in the substance

Front 54

endothermic reaction

Back 54

a reaction that requires heat to proceed; has a positive ∆Hrxn

Front 55

enthalpy (H)

Back 55

the state function that is used to denote heat changes in a chemical process

Front 56

enthalpy of formation (∆Hf)

Back 56

the heat that is absorbed or given off when a substance is produced from its elements at standard temperature and pressure

Front 57

enthalpy of reaction (∆Hrxn)

Back 57

the heat that is absorbed or given off by a reaction at standard temperature and pressure

Front 58

entropy (S)

Back 58

the state function that is a measure of the disorder of a system

Front 59

equilibrium

Back 59

the point in a reversible reaction where the rate of the forward reaction equals the rate of the reverse reaction

Front 60

equilibrium constant (K)

Back 60

describes the extent to which a reversible reaction proceeds before reaching the equilibrium point

Front 61

equilibrium expression

Back 61

expression that relates the concentrations of the products and starting materials to the equilibrium constant

Front 62

exact mass

Back 62

the mass of 1 mole of a pure isotope of an element

Front 63

excited state

Back 63

a high-energy state attained by an electron on absorbing heat energy

Front 64

exothermic reaction

Back 64

a reaction that produces heat; has a negative ∆Hrxn

Front 65

factor analysis

Back 65

process used to convert from one unit system to another by using conversion factors set up so as to cancel out the original unit

Front 66

first law of thermodynamics

Back 66

states that the change in the internal energy of a system equals the sum of heat and work energies of the system

Front 67

formal charge

Back 67

the charge of an atom in a lewis structure that occurs when the number of electrons brought into the molecule by that atom differs from the number of electrons that the atom has in the structure

Front 68

free energy (G)

Back 68

the measure of the energy of a reaction that is available to do work; the sign of the change in free energy ∆G is used to determine whether the reaction is spontaneous

Front 69

freezing point depression

Back 69

a colligative property of solutions that decreases the melting point of a solvent due to the presence of solute particles

Front 70

gas constant (R)

Back 70

has the value .08206 L atm/mole K; has the value 8.314J/mole K when used with thermodynamic functions

Front 71

group

Back 71

the elements in the same column of the periodic table

Front 72

half-life (t1/2)

Back 72

the time it takes for 50% of the reactant to convert to product

Front 73

half-reaction

Back 73

either the oxidation half or the reduction half of an oxidation-reduction reaction

Front 74

halogens

Back 74

the elements in group VIIIA

Front 75

heat

Back 75

energy that flows into or out of a system due to a difference in temperature between the system and its surroundings when they are in thermal contact

Front 76

heat capacity (C)

Back 76

the heat required to raise the temperature of a substance by 1 degree C; has the units J/C

Front 77

heat of fusion (∆Hfus)

Back 77

the heat required to convert 1 mole of substance in the solid state to the liquid state at the melting point of the substance

Front 78

heat of vaporization (∆Hvap)

Back 78

the heat required to convert 1 mole substance in the liquid state to the gaseous state at the boiling point of the substance

Front 79

henry's law

Back 79

states that the amount of gas that dissolves in a solvent is directly proportional to the pressure of that gas above the solution

Front 80

hess' law

Back 80

states that the sum of the ∆Hs for individual reactions equal the ∆Hrxn of the sum reaction

Front 81

hund's rule

Back 81

when filling an orbital, each orientation gets 1 electron before any are paired up in order to maximize the number of parallel spins

Front 82

hybridized orbitals

Back 82

orbitals that are hybrids of atomic orbitals of the same shell

Front 83

hydrogen-bonding

Back 83

the intermolecular force that is found in liquid or solid samples of covalent compounds that contain an O--H, F--H, or an N--H bond

Front 84

ideal gas

Back 84

a gas that exhibits no intermolecular interactions

Front 85

ion

Back 85

a species that has a net charge

Front 86

ionic compound

Back 86

a compound that is made of cations and anions so that the net charge is zero

Front 87

ionic radius

Back 87

the radius of an ion

Front 88

ionization energy

Back 88

the energy required to remove an electron from the valence shell, producing a cation

Front 89

isotope

Back 89

different forms of an element that have different numbers of neutrons, but equivalent protons, in the nucleus

Front 90

joule (J)

Back 90

the SI unit of heat energy that is equivalent of kg m^2/s^2

Front 91

kinetic energy

Back 91

energy of motion

Front 92

kinetic molecular theory of gas

Back 92

a model for gas behavior that consists of five assumptions that explains the behavior of ideal gases

Front 93

kinetics

Back 93

the study of reaction rates

Front 94

Kw

Back 94

the ion product constant for water; equivalent to 1.0*10^-14 at 25 degrees celsius

Front 95

lanthanides

Back 95

elements that have the 4f orbital as the valence orbital; also called the rare earth metals

Front 96

lattice network

Back 96

the orderly array of ions in a solid compound, characterized by alternating positions of positive and negative charge

Front 97

le chatelier's principle

Back 97

states that if a system that is at equilibrium is subjected to a change in conditions, the equilibrium will shift to counteract the change

Front 98

lewis structure

Back 98

a model that shows the positions of all valence electrons in a molecule, either as bonds or as lone pairs

Front 99

limiting reagent

Back 99

the reactant in a reaction that is completely used up, and therefore is the compound that is used to calculate the theoretical yield of product formed

Front 100

linear

Back 100

the geometry of the orbitals of an sp-hybridized atom where all bond angles are 180 degrees

Front 101

lone pair

Back 101

a pair of electrons that occupies a hybridized orbital

Front 102

magnetic quantum number

Back 102

the quantum number that describes the orientations allowed for an orbital; it has all integer values from -1 to +1

Front 103

main group elements

Back 103

the elements of groups IA-VIIIA that have either an s orbital or a p orbital as valence orbital; also called representative elements

Front 104

manometer

Back 104

instrument used to measure the pressure of gases inside a container

Front 105

metal

Back 105

element found to the left of the stairline on the periodic table; metals always lose electrons to form cations in compounds

Front 106

metalloid

Back 106

element found along the stairline of the periodic table that show characteristics of both metals and nonmetals

Front 107

molality (m)

Back 107

a concentration unit that is equivalent to mole solute per kg of solvent

Front 108

molarity (M)

Back 108

a concentration unit that is equivalent to mole solute per liter of solution

Front 109

molar mass

Back 109

the weighted average of the masses of all the known isotopes of an element; it is the mass of 1 mole of a natural sample of the element

Front 110

mole

Back 110

number of particles equivalent to 6.022*10^23

Front 111

molecular formula

Back 111

the actual chemical formula of the fundamental unit of a substance

Front 112

mole fraction (X)

Back 112

calculated by dividing the mole amount of one substance in a mixture by the total moles

Front 113

natural abundance

Back 113

the percentage of an isotope in a natural sample of element

Front 114

nernst equation

Back 114

used to calculate the nonstandard cell potential when concentrations of solutions are other than 1 M

Front 115

net ionic equation

Back 115

a balanced equation that includes only the ions that are reacting and the insoluble product that is formed in a precipitation reaction

Front 116

neutron

Back 116

a neutral particle with mass that is found in the nucleus of an atom

Front 117

nomenclature

Back 117

the system of rules used to name ionic and covalent compounds

Front 118

nonmetals

Back 118

the elements found to the right of the stairline in the periodic table, plus hydrogen

Front 119

nucleus

Back 119

the core of an atom that consists of the protons and neutrons, and is the location of the mass of the atom

Front 120

octahedral

Back 120

the geometry of the orbitals of an sp^3d^2 hybridized atom, where all the bond angles are 90 degrees

Front 121

orbital

Back 121

a three-dimensional area about the nucleus of an atom where the probability of find an electron is greater than 95%

Front 122

orbital diagram

Back 122

pictures the orbitals as sets of lines, one for each orientation of the orbital, and shows the electrons as arrows

Front 123

order of reactant

Back 123

the exponent of the reactant's concentration in the rate law of a reaction; the most common orders are zero-order, first-order, and second-order

Front 124

osmotic pressure

Back 124

the pressure that water exerts across a semipermeable membrane due to a difference in the concentrations on either side of the membrane

Front 125

oxidation

Back 125

loss of electrons

Front 126

oxidation number

Back 126

value assigned to an atom or ion that is used to track the gain or loss of electrons in an oxidation-reduction reaction

Front 127

oxidation-reduction reaction

Back 127

reaction where electrons are transferred from one species to another

Front 128

pauli exclusion principle

Back 128

states that no two electrons in an atom can have the same set of quantum numbers

Front 129

percent composition by mass

Back 129

the percent by mass of each element in a compound; it is determined by dividing the mass of each element by the total mass of the compound

Front 130

period

Back 130

the elements in the same row of the periodic table

Front 131

pH scale

Back 131

a logarithmic scale from 0 to 14 of values that are equivalent to the negative log of the hydronium ion concentration; less than 7 is acidic, 7 is neutral, and greater than 7 is basic

Front 132

phase change

Back 132

a change from one state of matter to another; it occurs at constant temperature

Front 133

phase diagram

Back 133

a plot of pressure versus temperature that shows the different phases for a substance

Front 134

photon

Back 134

the smallest particle of light possible; it has energy equivalent to hv.

Front 135

Pi bond (π)

Back 135

a covalent bond between two atoms that is in addition to the sigma bond; is made from overlapping p orbitals

Front 136

polyprotic acid

Back 136

an acid that has more than one acidic proton

Front 137

precipitate

Back 137

the insoluble solid product of a reaction

Front 138

precipitate reaction

Back 138

occurs when two solutions are mixed together, and the cation from one solutions reacts with the anion from the other solution to form an insoluble product

Front 139

pressure (P)

Back 139

force exerted by gases due to collisions with the walls of the container

Front 140

principle quantum number (n)

Back 140

the quantum number that describes the shell; can be an integer from 1 to 7

Front 141

proton

Back 141

a positively charged particle that has mass and is found in the nucleus of an atom

Front 142

quantum numbers

Back 142

the variables in each wave function of the Schrodinger series of equations;they include n, l, m1, and mS

Front 143

Raoult's law

Back 143

allows calculation of the vapor pressure lowering

Front 144

rate constant (K)

Back 144

temperature-dependent constant for a reaction

Front 145

reaction rate

Back 145

states the relationship of the rate of a reaction to the rate constant and to the concentrations of the reactants and their orders

Front 146

reaction quotient (Q)

Back 146

a value obtained by using nonequilibrium concentrations or pressure in the equilibrium expression for a reaction

Front 147

real gases

Back 147

gases that exhibit intermolecular forces at high pressures and/or small volume

Front 148

reduction

Back 148

the gain of electrons

Front 149

resonance structures

Back 149

different lewis structures for the same compound; differ only in the placement of valence electrons

Front 150

salt bridge

Back 150

connects the two half-cell solutions of a voltaic cell, and allows the movement of anions toward the anode and cations toward the cathode

Front 151

second law of thermodynamics

Back 151

states that the total entropy of a system and its surroundings always increases for a spontaneous reaction

Front 152

sigma bond

Back 152

the main bond between two atoms in a covalent compound or ion

Front 153

single displacement reaction

Back 153

an oxidation-reduction reaction that occurs when an element reacts with an ionic compound; the element becomes a cation and the original cation becomes an element

Front 154

solubility

Back 154

the extent to which a compound dissolves in a solvent; it is temperature-dependent; its units can be g/L or mole/L

Front 155

solubility product constant (Ksp)

Back 155

the equilibrium constant for the dissolving of a sparingly soluble inorganic compound in water

Front 156

solute

Back 156

a substance that is dissolved in a solvent

Front 157

solution

Back 157

consists of a solute dissolved in a solvent; is transparent

Front 158

solvent

Back 158

substance that dissolves a solute; is present in the greatest quantity

Front 159

specific heat (c)

Back 159

the heat required to raise the temperature of 1 gram of a substance by 1 degree celsius; has the units J/g

Front 160

spin quantum number (mS)

Back 160

the quantum number that describes the spin of an electron in one individual orientation of an orbital; has value ±1/2

Front 161

spontaneous reaction

Back 161

a reaction that proceeds to the right as written

Front 162

standard cell voltage (Ecell)

Back 162

the voltage generated by an electrochemical cell under the standard conditions of 25 degrees C, 1M concentrations, and 1 atm pressure

Front 163

strong acid

Back 163

an acid that fully dissociates in water solution

Front 164

strong base

Back 164

a base that fully dissociates in water solution

Front 165

tetrahedral

Back 165

geometry of the orbitals of an sp^3 hybridized atom, where all the bond angles are 109.5

Front 166

third law of thermodynamics

Back 166

states that a substance that is perfectly crystalline at 0K has an entropy of zero

Front 167

transition elements

Back 167

those metals that have a d orbital as their valence orbital; also called the nonrepresentative elements

Front 168

trigonal bipyramid

Back 168

the geometry of the obritals of an sp^3d hybridized atom, where the bond angles of the tree atoms in the place are 120, and those of the two atoms that bisect the place are 90 from the plane

Front 169

trigonal planer

Back 169

the geometry of the orbitals of an sp^2 hybridized atom, where all bond angles are 120

Front 170

triple point (T)

Back 170

the point on a pressure-temperature phase diagram where three phases coexist in equilibrium

Front 171

valence shell electron pair repulsion theory (VSPER)

Back 171

predicts the shape of molecules by assuming that areas of electron density will get as far from each other as possible

Front 172

Van der Waals equation

Back 172

contains correction factors for volume and pressure to better approximate the behavior of real gasses

Front 173

vapor pressure

Back 173

property of a liquid that results in an equilibrium being established between the liquid state and the vapor state when the liquid is in a closed container

Front 174

vapor pressure lowering

Back 174

a colligative property of solutions that lowers the vapor pressure of a solvent due to the presence of solute particles

Front 175

voltaic cell

Back 175

uses a spontaneous oxidation-reduction reaction, divided into two half-cells, to generate electricity

Front 176

weak acid

Back 176

an acid that dissociates only to a small extent in water solution

Front 177

weak base

Back 177

a base that produces only a very small amount of hydroxide ion in water solution

Front 178

How is the molar mass of a molecule calculated?

Back 178

The molar mass of a molecule is calculated by adding up the molar masses of the individual constituent elements of the molecule.

EX: KMnO4
K=39.10 g/mole
Mn=54.94 g/mole
O=16.00 g/mole *4 atoms
Summing these, the molar mass of potassium permanganate is 154.04 g/mole.

Front 179

How is percentage composition by mass determined?

Back 179

The percentage composition by mass of each element in a compound is found by determining the total mass of each element and then diving each element's mass by the total mass of the compound.

K2Cr2O7

K=39.10 g/mole * 2 mole=78.20 g
Cr=52.00 g/mole * 2 mole=104.0 g
O=16.00 g/mole * 7 mole=112.0 g

Summing these values gives a total mass of 294.2g. Thus,

K=78.20g/294.2g * 100=26.58%
Cr=104.0g/294.2g * 100=35.35%
O=112.0g/294.2g * 100=38.07%

Front 180

What are the four orbitals?

Back 180

s, p, d, and f

Front 181

CN-

Back 181

cyanide

Front 182

OH-

Back 182

hydroxide

Front 183

O2 -2

Back 183

peroxide

Front 184

MnO4 -

Back 184

permanganate

Front 185

CrO4 -2

Back 185

chromate

Front 186

Cr2O7 -2

Back 186

dichromate

Front 187

CO3 -2

Back 187

carbonate

Front 188

HCO3 -

Back 188

hydrogen carbonate

Front 189

PO4 -3

Back 189

phosphate

Front 190

HPO4 -2

Back 190

hydrogen phosphate

Front 191

H2PO4-

Back 191

dihydrogen phosphate

Front 192

PO3 -3

Back 192

phosphite

Front 193

HPO3 -2

Back 193

hydrogen phosphite

Front 194

H2PO3-

Back 194

dihydrogen phosphite

Front 195

SO4 -2

Back 195

sulfate

Front 196

HSO4-

Back 196

hydrogen sulfate

Front 197

SO3 -2

Back 197

sulfite

Front 198

HSO3-

Back 198

hydrogen sulfite

Front 199

NO3-

Back 199

nitrate

Front 200

NO2-

Back 200

nitrite

Front 201

ClO4-

Back 201

perchlorate

Front 202

BrO4-

Back 202

perbromate

Front 203

IO4-

Back 203

periodate

Front 204

ClO3-

Back 204

chlorate

Front 205

BrO3-

Back 205

bromate

Front 206

IO3-

Back 206

iodate

Front 207

ClO2-

Back 207

chlorite

Front 208

BrO2-

Back 208

bromite

Front 209

IO2-

Back 209

iodite

Front 210

ClO-

Back 210

hypochlorite

Front 211

BrO-

Back 211

hypobromite

Front 212

IO-

Back 212

hypoiodite

Front 213

NH4+

Back 213

ammonium

Front 214

H2O2

Back 214

peroxide

Front 215

PH3

Back 215

phosphine

Front 216

AsH3

Back 216

arsine

Front 217

give the prefixes used in naming binary covalent compounds
(1-10)

Back 217

mono, di, tri, tetra, penta, hexa, hepta, octa, nona, and deca.

Front 218

expand on the angular momentum quantum number

Back 218

The angular quantum momentum number can be any integer value from 0 up to n-1. A given n shell contains all the orbitals from l=0 up to l=n-1.

The l=0 orbital is called the s orbital. It is spherical with the nucleus at the center of the sphere. The s orbital can hold up to 2 electrons.

l=1 orbital is called the p orbital. It is dumbbell shaped with 2 lobes and a node at the nucleus. The p orbital can hold up to 6 electrons.

l=2 orbital is called the orbital and it has various shapes, including 4 lobes. The d orbital can hold up to 10 electrons.

The l=3 orbital is called the f orbital and it also has various shapes, including 8 lobes. The f orbital can hold up to 14 electrons.

Front 219

expand on the magnetic quantum number

Back 219

magnetic quantum number is 2l+1

For the s orbital l=0 and m1=0. There is one orientation; it is labeled m1=0 and it can hold up to 2 electrons.

For the p orbital, l=1 and m1=-1, 0, +1. There are three orientations, one along the x axis, one along the y axis, and the third along the z axis. Each orientation has an m1 label, and each orientation can hold 2 electrons, for a total of 6 electrons.

For the d orbital l=2 and m1=-2, -1, 0, +1, +2. There are 5 different orientations and each has an m1 label. The d orbital can hold a total of 10 electrons.

For the f orbital, l=3 and m1=-3, -2, -1, 0, +1, +2, +3. There are 7 orientations and each has an m1 label. The f orbital can hold a total of 14 electrons.

Front 220

How many shells are there?

Back 220

7 possible shells.

Front 221

expand on the notion of shells

Back 221

The 1-shell contains the 1s orbital for a total of 2 electrons.
The 2-shell contains the 2s and 2p orbitals for a total of 8 electrons.
The 3-shell contains the 3s, 3p, and 3d orbitals, for a total of 18 electrons.
The 4-shell contains the 4s, 4p, 4d, and 4f orbitals.
The 5-shell contains the 5s, 5p, 5d, and 5f orbitals. There is room for a 5g orbital, but an element with this many electrons has not yet been discovered.
The 6-shell contains the 6s, 6p, and 6d orbitals.
The 7-shell contains the 7s and 7p orbitals. Higher orbitals are also known for these two shells, but elements with that many electrons are unknown.

Front 222

Name the elements that have anomalous electron configurations.

Back 222

Cr, Cu, Nb, Mo, Pd, and Ag.

Front 223

Explain the relationship between group number and number of electrons in an element's valence orbital.

Back 223

Within a group, every atom has the same number of electrons in its valence orbital.

Front 224

Explain the relationship between a periodic period and electron numbers.

Back 224

Within a period, electrons are added sequentially from left to right to fill the orbitals within the shells. The period number (1-7) corresponds exactly to the shell number for the s and p orbitals within that period.

Front 225

Discuss the periodic trend in ionization energy (I).

Back 225

Elements that have fewer electrons in their valence orbital have lower ionization energies. Thus, the elements in group I have the lowest first ionization energies in their respective periods; those in group VIII have the highest. Further, ionization energy decreases as one goes down a group, because electrons that are held in higher n value shells are farther from the nucleus, and held less tightly.

Front 226

Discuss the periodic trend in electron affinity.

Back 226

Generally, the electron affinity increases going across a period to group VII. It then drops, and then increases again going across the next period. Within a group, the electron affinities are approximately equal. Electron affinity is lower to produce a half-full or a full valence orbital, and it is higher if one is adding an electron to an already half-full or full orbital.

Front 227

Discuss the periodic trend in electronegativity.

Back 227

Electronegativity generally increases going across a period and decreases going down a group.

Front 228

Discuss the periodic trend in effective nuclear charge.

Back 228

The effective nuclear charge (Zeff) increases going across a row and up a column; the attractive force on the electrons increases and the atomic radius decreases.

Front 229

Discuss the periodic trend in atomic radii.

Back 229

Generally, the size decreases going across a period because as the electron number increases, the attraction to the nucleus increases, thus the atomic radius decreases.
Going down a group, the shell number increases and Zeff decreases, thus the atomic radius increases.

Front 230

Discuss the periodic trend in ionic radii.

Back 230

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Front 231

Discuss the periodic trend in bonding between ions.

Back 231

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Front 232

How many electrons are needed to fill the shell of the second-row atoms carbon, nitrogen, oxygen, and fluorine?

Back 232

8 electrons

Front 233

How many electrons in Boron's valence shell when it is bonding normally?

Back 233

6 electrons

Front 234

How many electrons to fill the valence shell of hydrogen?

Back 234

2 electrons

Front 235

How does one determine an atom's valence electron number?

Back 235

The number of valence electrons of an atom is the same as the atom's group number.

Front 236

Boyle's Law

Back 236

Pressure of a gas is inversely related to the volume of a gas at constant temperature. In other words, the pressure times the volume equals a constant for a given amount of gas at a constant temperature:

PV=R when R is the ideal gas constant at .08206 L atm/mol K.

Front 237

Ideal Gas Law

Back 237

Combining Boyle's law, Charles' law, and Avogadro's law, we get PV=nRT.

Front 238

Give the value for the ideal gas constant.

Back 238

.08206 L atm/mol K.

Front 239

Describe the two major ways to use the Ideal Gas Law.

Back 239

The first method involves changing conditions. If there are initial conditions that are changed, one can solve for any unknown final condition. The mole amount, n, and the gas constant, R, are constant, thus: (PiVi/Ti)=(PfVf/Tf). If five of the six variables are given, the sixth variable can be solved for. If any value remains constant, it falls out of the equation.

The second way to use the Ideal Gas Law is under a set of conditions. There are four variables (P,V,T, and n). If three of them are given, the fourth can be solved by using PV=nRT.

Front 240

Explain Dalton's Law and how it is generally used.

Back 240

Dalton's Law states that each gas in a mixture exerts its own pressure, and the total of each gas' partial pressure equals the total pressure in the container.

At constant V and T, Pa+Pb+Pc=Ptotal for gases A, B, and C in the mixture. Thus, Ptotal=ntotalRT/V. Each gas consists of a fraction of the entire amount, ntotal. Each mole fraction is calculated.

EX: Calculate the partial pressure of each gas in a ballon that contains 50.97g nitrogen, 23.8g helium, and 19.5g argon at a total pressure of 2.67 atm.