Understanding States of Matter and Chemical Bonds

Solids

Compact because they don't try to fit their container.

Metallic Bonding

Atoms share electrons in a 'sea of delocalized electrons,' leading to strong attraction.

Intermolecular Forces

Hold molecules together in solids.

Liquids

Take the shape of their container.

Gases

Exhibit the weakest attraction forces.

Melting Point

The temperature at which a solid transitions to a liquid.

Boiling Point/Point of Vaporization

The temperature at which a liquid transitions to a gas.

Volatile

A substance that vaporizes easily.

Evaporation

Observed when a substance vaporizes.

Gasoline

Smelled immediately when exposed to air due to rapid evaporation.

Ammonia

Readily evaporates, producing a strong odor.

Coffee

Contains volatile organic compounds that contribute to its aroma.

New Car Smell

Caused by volatile organic compounds.

Expo Markers

Contain volatile organic compounds that allow the pigment to spread, resulting in a noticeable smell.

Diffusers

Oils evaporate, releasing their scent into the room.

Metals

Found on the left side of the periodic table.

Non-metals

Found on the right side of the periodic table.

Metalloids

Located on the staircase in between metals and non-metals.

Group 1 Metals

Readily undergo chemical reactions.

Oxidation

The loss of electrons, increasing the positive charge.

Reduction

The gain of electrons, which means the charge will go down and become negative.

Unit Conversion

1 unit = 1000 milliunits

Kilounit Conversion

1 kilounit = 1000 units

Liter Conversion

1 liter = 1000 milliliters

Kilogram Conversion

1 kilogram = 1000 grams

Density

Mass/Volume grams/milliliter Relates mass and volume

Molar Mass

Grams/Moles grams/mole Converts grams to moles and vice versa

Avogadro's Number

Pieces/Mole pieces/mole Relates pieces (atoms, molecules, etc.) to moles

Molarity

Moles/Liters moles/liter Converts moles to liters and vice versa

Isotopes

Variations of an element with different numbers of neutrons.

Ions

Formed by changing the number of electrons in an atom, resulting in a change in charge.

Cations

Positive ions

Anions

Negative ions

Changing Protons

Changing the number of protons changes the element itself, altering all physical and chemical properties.

Electron Configuration

Understanding electron arrangements in elements.

S Orbital

Holds 2 electrons.

P Orbital

Holds 6 electrons.

D Orbital

Holds 10 electrons.

F Orbital

Holds 14 electrons.

Periodic Trends

Dictate how certain properties of elements change across the periodic table.

Atomic Radii

Large atoms are found in the lower left of the periodic table; small atoms are found in the upper right.

Electronegativity

An atom's pull on shared valence electrons.

Ionization Energy

The energy it takes to remove an electron from an atom.

Trend Summary

Small atoms: Strong attraction, high electronegativity, high ionization energy. Large atoms: Weak attraction, low electronegativity, low ionization energy.

Successive Ionization Energies

The amount of energy required increases with each electron removed.

Covalent Bonding

Sharing electrons between two non-metals.

Single Bond

A bond formed by sharing two electrons.

Double Bond

A bond formed by sharing four electrons.

Triple Bond

A bond formed by sharing six electrons.

Covalent Bond Properties

Triple bonds are the strongest, while single bonds are the longest and weakest.

Octet Rule

Covalent bonding is about filling the octet (valence shell) by sharing electrons.

London Dispersion Forces (LDF)

The weakest IMF, arising from temporary shifts in the electron cloud which creates temporary dipoles.

Dipole-Dipole Attraction

Occurs between polar molecules where the positive end of one molecule attracts the negative end of another.

Hydrogen Bonding

A strong type of dipole-dipole attraction occurring when a hydrogen atom bonded to fluorine, oxygen, or nitrogen is attracted to a lone pair of electrons on another atom.

Ionic Bonding

Involves the transfer of electrons from one atom to another, resulting in positive and negative ions.

Neutral Compound

When building ionic compounds, charges must cancel out to create a neutral compound.

Redox Reactions

Metals oxidize to empty their valence shell and become positive ions; non-metals reduce to fill their valence shell and become negative ions.

Sigma (σ) Bonds

Sigma bonds are always the first bond formed between two atoms.

Pi (π) Bonds

Bonds formed by the sideways overlap of p-orbitals.

Pi bonds

Extra bonds, such as second or third bonds in double or triple bonds.

Covalent Compounds

The name indicates the number of each element present.

Dinitrogen tetraoxide

The chemical formula N2O4.

Tetraphosphorus decaoxide

The chemical formula P4O10.

Ionic Compounds

Do not use prefixes to indicate the number of atoms; the name is simply the metal name followed by the non-metal with an '-ide' ending or the polyatomic ion name.

Oxidation State

The charge of an element in a compound, which must balance with the charges of negative ion(s) attached.

Hydrogen oxidation state

1

Group 1 elements oxidation state

1

Group 2 elements oxidation state

2

Formula Mass

The mass of a single formula unit, expressed in atomic mass units (amu).

Percent Composition by Mass

Calculated using the formula: PercentComposition = (Mass of Element/Mass of Compound) ∗100.

Empirical formula

The simplest whole-number ratio of atoms in a compound.

Molecular formula

Represents the actual number of atoms of each element in a molecule; it's a multiple of the empirical formula.

Example of empirical and molecular formulas

For CH4, the empirical and molecular formulas are the same since the 1:4 ratio cannot be reduced further.

Chemical Equations

Representations of chemical reactions using symbols and formulas.

Word Equations

Descriptive representations of chemical reactions.

Balancing Chemical Equations

Ensuring the number of atoms for each element is the same on both sides of the equation.

Synthesis Reaction

Two or more reactants combine to form a single product.

Decomposition Reaction

A single reactant breaks down into two or more products.

Combustion Reaction

A reaction with oxygen that produces carbon dioxide and water.

Single Displacement Reaction

A reaction where one element replaces another in a compound.

Double Displacement Reaction

A reaction where the positive and negative ions of two reactants switch places.