Chemistry Chapter 3

Atomic Theory

The scientific theory that matter is composed of small, indivisible particles called atoms

______ cannot be created, divided, or destroyed (Dalton's Atomic Theory)

Atoms

Atoms combine in whole-number ratios to form _____ (Dalton's Atomic Theory)

compounds

_______ involve the rearrangement of atoms (Dalton's Atomic Theory)

Chemical reactions

Atoms are ______ (contain protons, neutrons, and electrons) (How has Dalton's theory been modified)

divisible

Atoms of the same element can have different _____ (isotopes). (How has Dalton's theory been modified)

masses

Atoms can change in ______ (How has Dalton's theory been modified)

nuclear reactions

Law of Conservation of Mass

Matter cannot be created or destroyed in chemical reactions; atoms are simply rearranged

Law of Definite Proportions

A compound always has the same elements in the same mass ratio

Law of Multiple Proportions

When two elements form multiple compounds, their mass ratios are simple whole numbers

Proton

+1 charge, in nucleus, mass = 1 amu

Electron

-1 charge, in electron cloud, mass ~ 1/1836 amu

Neutron

0 charge, in nucleus, mass = 1 amu

Atomic Number

The number of protons in an atom, which determines the element

Atomic Mass

The weighted average mass of an element's isotopes

Isotopes

Atoms of the same element with different numbers of neutrons

Aufbau Principle

Electrons fill lowest-energy orbitals first

Hund's Rule

Electrons fill orbitals singly before pairing up

Pauli Exclusion Principle

No two electrons can have the same four quantum numbers

s-orbital

Spherical

p-orbital

Dumbbell-shaped

d-orbital

Cloverleaf-shaped

f-orbital

Complex shape

Groups (columns)

Elements in the same group have similar chemical properties

Periods (rows)

Elements in the same period have increasing atomic number

Atomic Radius

Increases down a group, decreases across a period (Average bonding radii when bound to another atom)

lonization Energy

Increases across a row, decreases down column

Electronegativity

Increases across a period, decreases down a group

Electron Affinity

Follows a similar trend as electronegativity

Ionic Bond

Transfer of electrons (metal to nonmetal)

Covalent Bond

Sharing of electrons (nonmetal to nonmetal)

Metallic Bond

Delocalized electrons moving in a metal lattice

What are the three types of chemical bonds?

Ionic, Covalent, Metallic

What are the major types of chemical reactions?

Synthesis (Combination), Decomposition, Single Replacement, Double Replacement, Combustion

Synthesis (Combination)

A + B → AB

Decomposition

AB → A + B

Single Replacement

A +ВС → AC + В

Double Replacement

AB + CD → AD + СВ

Combustion

Hydrocarbon + 02 → CO2 + H20

Stoichiometry

The study of quantitative relationships in chemical reactions

Mole Concept

1 mole = 6.022 × 1023 particles (Avogadro's number)

Boyle's Law

P1V1 = P2V2 (Pressure-Volume, inversely related)

Charles's Law

V1/T1 = V2/T2 (Volume-Temperature, directly related)

Ideal Gas Law

Pv = nRT

Enthalpy (ДН)

The heat change in a reaction

Periodic Law

The elements are arranged in order of increasing mass, certain sets of properties recur periodically

Electron Configurations

Shows the particular orbitals that electrons occupy for the atom

The farther a principle level is from a nucleus _______

Gets larger, holds more electrons, electrons have higher energies

Sub shells

Angular Momentum Quantum Number (s, p, d, and f)

s

Shell: 1, # of orbitals: 1, Electron Capacity: 2, e- in orbital: 2

s,p

Shell: 2, # of Orbitals: 1,3, Electron Capacity: 8, e- in orbitals: 2,6

s,p,d

Shell: 3, # of Orbitals: 1,3,5, Electron Capacity: 18, e- in orbitals: 2,6,10

s,p,d,f

Shell: 4, # of orbitals: 1,3,5,7, Electron Capacity: 32, e- in orbital: 2,6,10,14

Electron Configuration

Shows the particular orbitals that electrons occupy for the atom

________ describes the attractions and repulsion’s between charged particles. The strength of the interaction increases as the size of the charges increase

Coulomb’s Law

_____ an electron from the full effects of the nuclear charge by repulsion of other electrons

Shielding

______ of the electron cloud by an electron now feels the full effects of the nuclear charge

Penetration

Electrons occupy the ____

lowest energy orbitals available

The group number of a main group element is _______

equal to the number of valance electrons for that element

The row number of a main group element is _____

equal to the highest principle quantum number of that element

Why do elements in a given group of the periodic table have similar properties?

Similar electron configurations in their valance shells- the outermost principle energy level

Valance Shell

Outermost electron shell of an atom

Valance Electron

An electron in the valance shell of an atom

Core electron

an electron that is not part of the valance shell

Metals

Conduct heat and electricity, Form cations in solution, loses electrons in reactions- oxidized

Nonmetals

Electrical and thermal insulators, form anions and polyatomic anions, gain electrons in reactions- reduced

Paramagnetic

contains unpaired e- and attracted to magnetic field

Diamagnetic

Contains paired e- and is not attracted to magnetic field

Octet Rule

Elements undergo reactions to get 8 valance electrons

Electron Affinity (Definition)

The energy released on adding an electron to a single atom in the gaseous state

Ionization Energy (Def)

The energy required to remove one electron from a single atom in the gaseous state

Ionic Solids

Ions are attached by ionic bonds to their nearest neighbors. Compounds of this type are referred to as ionic compounds

The group numbers from 1A through 8A give the numbers of valance electrons for the elements in _____ (Group 1A, 1 Valance Electron, ns1)

each main group

Transition Metals Valance electrons include the ____ (Group 4b, 4 Valance Electrons, ns2nd2)

d electrons

Effective Nuclear Charge

The charge that the valance e- feel from the nucleus

Compounds are composed of atoms held together by chemical _____

Bonds

_____ form because they lower the potential energy of the charged particles (the electrons and protons) that compose atoms

Chemical Bonds

Chemical Bonds are Classified Into two main types

Ionic, Covalent

Ionic

Metals+Nonmetals, Transfer e-, Cation+Anion

Covalent

2 or more nonmetals, share e-, atom+atom

When a metal interacts with a nonmetal, it can transfer one or more of its electrons to the nonmetal. The metal atom then becomes a ______. The nonmetal atom becomes a _____

cation, anion

Molecular Compound

compound that consists of molecules rather than ions

Bond Length

The optimum distance between nuclei in a covalent bond

Chemical Formula

Indicates the elements that are present in the compound and the relative number of atoms or ions

Empirical Formula

Gives the relative # of atoms of each element in a compound (Hydrogen Peroxide-HO)

Molecular Formula

A formula that shows the # and kinds of atoms in one molecule of a compound (H2O2)

Structural Formula

A molecular representation that shows the connections among atoms by using lines to represent covalent bonds (H-O-O-H)

Molecular Model

More accurate and complete way to specify a compound

Ball and Stick molecular model

Represents atoms as balls and chemical bonds as sticks.x how the two connect reflects a molecules shape

Space Filling Molecular Model

Atoms fill the space between each other to more closely represent our best estimates for how a molecule might appear if scaled to visible size

Lewis structures focus on valence electrons because ______ involves the transfer or sharing of valance electrons between two or more atoms

Chemical bonding

Lattice Energy (Always Exothermic)

-E associated with the formation of a crystalline lattice of alternating ± ions in gaseous state

Born-Haber Cycle

Lattice energy generally negative, large amount of heat released when ions coalesce to form a crystalline lattice

Ionic compounds are ____. Cation and Anions combine to cancel charges

Neutral

______ bond almost exclusively covalently

Carbon Atoms

Formula Mass

= Number of atoms of 1st element in chemical formula X atomic mass of 1st element) + (Number of atoms of 2nd element in chemical formula X Atomic Mass of 2nd Element)

When two different elements combine, they form a _____

Binary compound, metals are always written before nonmetals

Coordinate covalent bond

Covalent bond that forms when both electrons are donated by the same atom

Polyatomic Ions

Composed of two or more atoms with a particular charge

Oxyanions

Anions containing oxygen and another element