Chem Final Exam review

Proton

Charge = +1; located in the nucleus

Neutron

Charge = 0; located in the nucleus

Electron

Charge = -1; located in the electron cloud

Atomic Number

Number of protons in an atom

Mass Number

Number of protons plus neutrons

Valence Electrons

Electrons found in the outermost energy level of an atom

Ion

An atom with a charge because it has gained or lost electrons

Positive Ion (Cation)

Atom that has lost electrons and has a positive charge

Negative Ion (Anion)

Atom that has gained electrons and has a negative charge

Electron Cloud

Region surrounding the nucleus where electrons are found

Aufbau Principle

Electrons fill orbitals from lowest energy to highest energy

Electron Filling Order

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p

Pauli Exclusion Principle

Two electrons in the same orbital must have opposite spins

Electron Repulsion

Electrons repel each other because they have negative charge

First Energy Level

Contains only the 1s sublevel

Ionic Bond

Transfer of electrons between atoms; usually metal + nonmetal

Covalent Bond

Sharing of electrons between atoms; usually nonmetal + nonmetal

Lewis Dot Structure

Diagram showing valence electrons as dots

Octet Rule

Atoms gain, lose, or share electrons to achieve 8 valence electrons

Noble Gas

Element that naturally has a full outer shell of electrons

Helium

Example of a noble gas

Neon

Example of a noble gas

Argon

Example of a noble gas

Krypton

Example of a noble gas

Matter

Anything that has mass and takes up space

Solid

Particles tightly packed and vibrating in place

Liquid

Particles close together and flowing past one another

Gas

Particles spread far apart and moving rapidly

Gas Particles

Far apart and moving quickly

Not a State of Matter

Crystalline

Physical Change

Change that does not create a new substance

Examples of Physical Change

Melting ice, boiling water, freezing water

Chemical Change

Change that creates a new substance

Evidence of Chemical Change

Gas production, temperature change, color change, precipitate formation

Examples of Chemical Change

Burning wood, rusting iron, digestion

Physical Property

Can be observed without changing the identity of a substance

Examples of Physical Properties

Color, density, boiling point

Chemical Property

Describes how a substance reacts

Example of Chemical Property

Reactivity with acid

Acid

Substance with pH below 7 that produces H+ ions

Properties of Acids

Sour taste, pH below 7, produces H+ ions

Examples of Acids

HCl, H2SO4, vinegar

Base

Substance with pH above 7 that produces OH- ions

Properties of Bases

Bitter taste, slippery feel, produces OH- ions

Examples of Bases

NaOH, NH3

Neutral Solution

pH = 7

Strong Base

pH between 13 and 14

pH 0-6

Acid

pH 7

Neutral

pH 8-14

Base

Neutralization Reaction

Acid + Base → Salt + Water

Example Neutralization

NaOH + HCl → NaCl + H2O

Synthesis Reaction

Two substances combine to form one product

Synthesis Pattern

A + B → AB

Example Synthesis

2Na + Cl2 → 2NaCl

Decomposition Reaction

One compound breaks apart into simpler substances

Decomposition Pattern

AB → A + B

Example Decomposition

2H2O → 2H2 + O2

Single Replacement Reaction

One element replaces another element in a compound

Single Replacement Pattern

A + BC → AC + B

Example Single Replacement

Zn + HCl → ZnCl2 + H2

Double Replacement Reaction

Ions switch partners between compounds

Double Replacement Pattern

AB + CD → AD + CB

Example Double Replacement

AgNO3 + NaCl → AgCl + NaNO3

Combustion Reaction

Hydrocarbon + Oxygen → Carbon Dioxide + Water

Combustion Requires

Oxygen

Combustion Products

Carbon dioxide and water

London Dispersion Forces

Weakest intermolecular force; present in all molecules

Stronger Dispersion Forces

Occur in larger molecules with more electrons

Dipole-Dipole Forces

Intermolecular forces that occur between polar molecules

Examples of Dipole-Dipole Molecules

H2O and NH3

Hydrogen Bonding

Strongest intermolecular force on this test

Hydrogen Bonding Requirements

Hydrogen bonded to N, O, or F

Examples of Hydrogen Bonding

HF, H2O, NH3

Why Hydrogen Bonding is Strong

N, O, and F are highly electronegative, creating strong attractions

Polar Molecule

Molecule with unequal sharing of electrons

Examples of Polar Molecules

H2O, NH3, CH3F

Nonpolar Molecule

Molecule with equal sharing of electrons

Example of Nonpolar Molecule

CH4

Weakest Dispersion Forces Example

CH4 because it is the smallest molecule listed

Valence Electrons Definition

Outer shell electrons

Covalent Bond Definition

Sharing electrons

Ionic Bond Definition

Transfer of electrons

Lewis Dot Structure Definition

Dots showing valence electrons

Octet Rule Definition

Atoms seek 8 valence electrons

Ion Definition

Charged atom

Noble Gas Definition

Element with a full outer shell

Electron Configuration Definition

Arrangement of electrons in an atom