Regents Chemistry - Master Outline

This JSON contains vocabulary-style flashcards for Regents Chemistry, covering topics from atomic structure to organic and nuclear chemistry.

Scientific Notation

Simplifying a number by indicating the number of places that the decimal can be moved as to eliminate the insignificant zeros present.

The Metric System

The system of units used in Chemistry.

Dimensional Analysis

A method to convert one unit to another.

Significant Figures

The numbers reported in a measurement are limited by the accuracy of the measuring tool.

Chemistry

The study of matter, its properties, its composition, and the energy changes involved.

Matter

Anything that has mass and occupies space.

Substance

Any variety of matter which has identical properties and composition.

Element

Cannot be broken down by chemical means.

Compound

Made up of many elements and can be broken down chemically.

Mixtures

Combinations of two or more pure substances in which each substance retains its own composition and properties.

Homogeneous Mixture

Does NOT contain any visibly different parts (same throughout).

Heterogeneous Mixture

Visibly different parts (not the same throughout).

Physical Property

Quality of a substance that can be observed or measured without changing the substance’s identity.

Chemical Property

Any of a material's properties that becomes evident during a chemical reaction.

Physical Change

Usually a change in phase while the substance stays constant. No changes are made chemically.

Chemical Change

Involves changes in the chemical composition of the compounds, no matter the phase.

Filtration

Used to separate suspended particles from mixtures usually through filter paper and a simple funnel.

Distillation

Used to separate solid-liquid mixtures and liquid-liquid mixtures (boiling point difference) such as water and alcohol.

Chromatography

To separate dyes and other soluble (dissolvable) materials from insoluble ones through different polarities of the materials.

Democritus

Greek philosopher proposed that all matter was composed of tiny indestructible / indivisible particles called atoms (atomos = Greek for indivisible).

Billiard Ball Model

Viewed the atom as a small solid sphere (aka Solid Sphere Model).

J.J. Thomson

Discovers electrons using the cathode ray experiment from William Crookes.

Plum Pudding Model

The atom was a sphere of positive electricity (which was diffused) with negative particles imbedded throughout after discovering the electron.

Gold Foil Experiment

Shot alpha particles at a thin layer of gold foil and made conclusions about the structure of an atom.

Bohr Model (Planetary Model)

Electrons travel in stationary orbits (called principal energy levels) around the nucleus.

Electron Cloud Model/Wave Mechanical Model

An atom consists of a dense nucleus composed of protons and neutrons surrounded by electrons that exist in different regions or clouds in which electrons would most likely be found (called orbitals).

Protons (p+)

Positive charge and weighs 1 amu (1 U) – located in the nucleus.

Neutrons (no)

No charge and weighs 1 amu (1 U) – located in the nucleus.

Electrons (e-)

Negative charge and weighs nothing – located outside and orbits around the nucleus (doesn’t affect the charge of the nucleus).

Chemical Symbol

Shorthand notation of a chemical’s name.

Atomic Number

Identifying number of an element = number of protons = number of electrons (in a neutral atom).

Atomic Mass

The mass of an element based on isotopic abundances. It is also the average mass of the element as it is found in nature (usually not a whole number).

Mass Number

Equal to the number of neutrons + protons.

Isotopes

an element that has the same number of protons (same atomic number) but different number of neutrons (different mass numbers).

Bohr Theory

Electrons travel in an orbit around the nucleus in Principal Energy Levels or PELs (discrete energy states). PELs are sometimes referred to as shells.

Ground State

Lowest energy level of an electron where it has not absorbed any energy to become excited.

Excited State

When an electron absorbs energy and shifts to a higher energy level.

Quanta

Specific amount of energy released when an electron goes from excited state to a lower energy state.

Valence Electrons

Electrons that are located in an atom’s outermost shell (energy level). These are the electrons that determine the chemical properties of an element

Lewis Dot Diagrams/Valence Dot Diagrams/Electron Dot Diagrams

Simple shorthand model representing the number of valence electrons in an atom

Spectral Lines/Balmer Series

When electrons are excited to a higher energy state and then they fall back down, the amount of energy that is released corresponds to a specific color of light.

Ions

An atom that has gained or lost an electron(s).

Cation

As an atom loses electrons it loses negative charge (because electrons are negative) and the atom will become positive.

Anion

As atoms gain electrons they gain a negative charge and become more negative.

Octet Rule

Atoms tend to gain, lose, or share electrons in order to acquire a full set of valence electrons, which is 8 electrons.

Duet Rule

Some atoms do not have enough protons to hold onto 8 electrons, instead they are satisfied with 2 electrons in their outermost principle energy level.

Electronegativity

The tendency of an element to attract electrons.

First Ionization Energy

The amount of energy it takes to remove the first valence electron from an atom.

Atomic Radii/Radius

The size of the atom from the center of the nucleus to its outermost electron.

Metallic Character

How closely to a metal an element behaves.

Nonmetallic Character

How closely to a nonmetal an element behaves.

Reactivity

For metals, the more reactive: the more easily the metal loses electrons. For nonmetals, the more reactive: the less easily a nonmetal loses electrons.

Ionic Radius

Metals get smaller as they become ions because they lose electrons. Nonmetals get larger as they become ions because they gain electrons.

Ductile

Can be rolled or pulled into wires.

Malleable

Can be hammered into thin sheets (think mallets).

Polyatomic Ions

Ions that consist of two or more different elements bonded together.

Stock System

A system of naming (using roman numerals) used for naming compounds that contain elements (usually transition metals, Groups 3-12) that have multiple oxidation states.

Molecule

A compound consisting of two or more nonmetals covalently bonded. In other words, molecules cannot contain a metal.

Nonpolar Covalent Bonds

A pure covalent bond in which there is an equal attraction (equal sharing) of electrons between the two elements involved.

Polar Covalent Bonds

A polar covalent bond is formed between different elements when there is unequal sharing because the elements have different values of electronegativity.

VSEPR Theory

Atoms in a molecule try to spread from one another as much as possible to reduce “like charge repulsion” between their outer electrons.

Intermolecular Forces

Forces of attraction between covalent molecules in the liquid and solid states.

Metallic Bonds

Electrostatic attraction (+ & -) between metal ions arranged in the lattice structure and free floating electrons.

Alloys

Mixtures of 2 or more elements, at least 1 is a metal

Chemical Formulas

Tells us which elements (qualitative) and how many atoms (quantitative) of each element are present.

Structural Formula

The entire molecule is drawn out showing all covalent bonds.

Molecular Formula

Indicates the total number of atoms of each element needed to form a covalently bonded substance (molecules are covalently bonded compounds: only between nonmetals).

Empirical Formula

The lowest ratio of the elements (smallest ratio of subscripts possible).

Reactants

Starting substances (what goes into the chemical process).

Products

Substances formed (what comes out of the chemical process).

The Law of Conversation of Mass

Matter is neither created nor destroyed. Therefore, chemical equations must show that matter is conserved.

Electrolyte

A substance that breaks apart in water, forming ions.

Mole

1 mole (abbreviated as mol) of a substance = 6.02 x 1023 particles of that substance (Avogadro’s Number).

Calculating GFM

The Gram Formula Mass, GFM, or molar mass of a compound is the sum of the masses of all the elements contained in the compound.

Mole Ratio

In a given balanced equation, the coefficients of each species (or substance) represent the number of moles of that species in the chemical equation.

Representative Particles

Any particle referred to in the problem.

Combustion

A reactant (hydrocarbon) in the presence of oxygen gas produces water and carbon dioxide.

Energy

The ability to do work (complete a task).

Kinetic Energy

Energy that is in motion (the energy that an object possesses by being in motion).

Potential Energy

Energy that is stored within an object (usually due to the objects position such as raised against gravity).

Temperature

The average kinetic energy of a molecule.

Kelvin

A scale similar to that of the Celsius scale. The Kelvin scale marks the zero point as the lowest temperature possible

Exothermic Reaction

When a reaction occurs and more energy is released than absorbed, then the reaction is said to be Exothermic.

Activation Energy (Ea)

The minimum amount of energy the reactants need to gain in order for the reaction to progress.

∆H or Enthalpy (Heat) of Reaction

The amount of heat or energy the reaction absorbs or releases. (can be thought of as energy change)

Endothermic Reaction

When more energy is absorbed than released, then the reaction is said to be Endothermic.

Activated Complex

The structure associated with the maximum energy point along the reaction pathway.

Heat Flow

Heat will flow from high to low.

Freezing

Changes from a liquid to a solid.

Melting

Changes from a solid to a liquid.

Condensation

Changes from a gas to a liquid.

Vaporization

Changes from a liquid to a gas.

Sublimation

Changes from a solid to a gas without passing through the intermediate state of a liquid.

Deposition

Changes from a gas to a solid without passing through the intermediate state of a liquid.

Kinetic Molecular Theory

Describes behavior of gases by treating them as particles with specific properties of size, motion, and energy.

Electronegativity

The tendency of an element to attract electrons.

Graham’s Law of Effusion

Gases diffuse at a rate inversely proportional to the square roots of their molecular masses.

Vapor Pressure

The equilibrium pressure of a vapor above its liquid (or solid); that is, the pressure of the vapor resulting from evaporation of a liquid (or solid) above a sample of the liquid (or solid) in a closed container.

Colligative Properties

A physical property of a solution that is affected by the number of dissolved particles, but not the identity of the dissolved solute.

Unsaturated Solution

A solution that does not have the maximum amount of solute dissolved.