Chemistry Fall Semester Review

What distinguishes a solid from a liquid?

Solid has fixed shape vs. liquid takes shape of its container.

What distinguishes a liquid from a gas?

Liquid takes shape of its container vs. gas has no specific volume or shape.

Law of Conservation of Matter and Energy

The total amount of matter and energy stays consistent over time and cannot be created or destroyed.

What are physical properties?

Characteristics observed without changing the chemical identity of an element; change in color, hardness, density, etc.

What are chemical properties?

A substance’s ability to undergo a chemical change or reaction; flammability, reaction with acid, reaction with oxygen, etc.

What are pure substances?

Forms of matter with a constant composition throughout.

What is a mixture?

A substance containing 2 or more elements or compounds that are not chemically bonded.

How are metals, nonmetals, and metalloids classified on the periodic table?

Metals are on the left and in the middle, nonmetals are on the right, and metalloids form a zigzag line between them.

What is accuracy?

How close a measurement is to the true or accepted value.

What is precision?

How close multiple measurements are to each other.

What are the two main regions of an atom?

Nucleus and electron cloud.

What are the 3 types of subatomic particles found in an atom?

Protons, neutrons, and electrons.

What are the two phases of mixtures?

Homogeneous and heterogeneous; uniform composition vs nonuniform composition.

How is the atomic number of an atom related to its structure?

The atomic number is equal to the number of protons in an atom’s nucleus.

What part of the atom is involved in the production of a chemical bond?

Valence electrons.

How are photons produced by an atom?

When an electron goes from its ground state to its excited state, back down to its ground state.

What is spectroscopy?

The study of the interaction between matter and electromagnetic radiation.

What are the 5 components of a wave?

Amplitude, wavelength, frequency, trough, crest.

What is the relationship between frequency and wavelength?

Inverse relationship.

What units are used to signify wavelength?

Meters.

What is the ground state of an atom?

The lowest energy state of an atom.

What is the excited state of an atom?

The highest energy state of an atom.

What is the principal quantum number?

Determines the distance of electrons from the nucleus of an atom.

What do quantum numbers describe?

The properties of electrons in an atom.

What are the 4 quantum numbers?

Principal (n), orbital (l), magnetic (ml), spin (ms).

How does n relate to the energy and distance of a main energy level from the nucleus?

As n increases, the energy of the main energy level increases.

What information is given by the orbital quantum number?

The shape of the orbital/sublevel.

What are sublevels/subshells?

Subdivisions within a main energy level that have orbitals of a certain shape.

What is the Aufbau principle?

An electron occupies the lowest energy level that can receive it.

What is Hund’s rule?

Half-fill orbitals to keep them even with parallel spins.

What did Democritus do?

Discovered that matter can be split until indivisible.

What did Rutherford do?

Discovered the nucleus and protons.

What did J.J Thompson do?

Discovered cathode (electron) waves and the magnetic field with charge to mass ratio (e/m).

What did Robert Millikan do?

Discovered charge and mass of electrons.

What is the Law of Multiple Proportions?

When two elements combine into more than one compound, the masses of each element mix into a small number ratio (1:2). Created by John Dalton.

What did cathode rays indicate about atoms?

That they are indivisible and contain electrons.

What is similar about the electron configurations of elements with similar properties?

They have the same number of valence electrons and similar outer electron configurations.

What is the relationship among the elements within a specific group (for the s and p block elements?)

They have the same number of valence electrons.

What are cations?

Positively charged ions.

What are anions?

Negatively charged ions.

Why does a solid hold its shape?

Its particles are tightly packed together.

What is an element?

A pure substance consisting of one type of atom.

What is a compound?

Two or more atoms that are chemically bonded together.

Why are elements and compounds considered to be pure substances?

They both have a uniform composition.

How does the kinetic theory of matter behave with the increase of temperature?

As temperature increases, the kinetic energy increases.

What is a solid in terms of particle motion?

Particles that are tightly packed together in a fixed position.

What are the characteristics of a liquid?

Has a definite volume, no definite shape, and takes the shape of its container.

What is a gas in terms of particle motion?

Particles are far apart and move rapidly.

What is a mixture?

A substance with two or more elements or compounds that are not chemically bonded.

What is a homogeneous mixture?

A mixture with a uniform composition throughout (saltwater, air, etc.)

What is a heterogeneous mixture?

No uniform composition throughout (sand and water, oil and vinegar, etc.)

What are the base units for length, mass, volume, and time?

Meter, kilogram, liter, second.

What is the shape of the S orbital and how many electron pairs can it hold?

Sphere shape; 2.

What is the shape of the P orbital and how many electron pairs can it hold?

Dumbbell shape; 6

What is the shape of the D orbital and how many electron pairs can it hold?

4-leaf clover; 10

What is the shape of the F orbital and how many electron pairs can it hold?

Too complicated; 14

What are valence electrons?

Electrons in the outermost shell of an atom that form chemical bonds.

What is a mole?

An SI unit for the amount of a substance (6.02×10²³).

How do you find the atomic mass of an element?

By looking at the top right corner of the element’s box on the periodic table.

What is the atomic mass of an element?

The weighted average mass of all naturally occurring isotopes.

What are isotopes?

Different forms of an element with the same number of protons, but a different number of electrons.

What is physical change?

Change in state or appearance of a substance.

What is chemical change?

Change in composition of a substance.

What are E.C.Ns and O.Ns?

Methods of describing the arrangement of electrons in an atom.

What is density?

Measure of mass per unit volume.

What are the methods for separating mixtures?

Filtration, distillation, evaporation, chromatography

What does the Pauli Exclusion principle state?

No two electrons in the same atom can have the same four quantum numbers; electrons in the same orbital must have opposite spins.

What are the factors on the electromagnetic spectrum from lowest to highest wavelength?

Gamma, x-rays, ultraviolet, visible light, infrared, microwaves, radio waves.