Physical Sci Reviewer

Element

A pure substance made up of one kind of atom.

Nucleosynthesis

The process of creating new atomic nuclei from preexisting nucleons (protons and neutrons).

Nuclear Reactions

The processes in which a nucleus either combines with another nucleus or splits into smaller nuclei.

Big Bang Theory

The accepted theory that explains the formation and expansion of the universe.

Singularity

The initial state of the universe before the Big Bang.

Inflation

The rapid expansion of the universe immediately after the Big Bang.

Cool Down

The subsequent decrease in temperature after the inflationary period.

Isotopes

Elements that possess the same atomic number but a different mass number.

Stellar Formation and Evolution

The process of a star's formation and its subsequent changes over time.

Fusion Shells

The regions in a star where successive nuclear reactions occur, leading to the production of new elements.

Hydrogen Core

The initial step in the formation of stars through nuclear fusion and the proton-proton chain reaction.

Carbon Formation

The process by which carbon is formed through the triple alpha process at high temperatures.

Stellar Explosion

The violent explosion that occurs when a red giant star exhausts its nuclear fuel, leading to a supernova.

Beta Decay

A type of radioactive decay in which a nucleus emits a beta particle (high-speed electron or positron).

S-process

The slow capture of neutrons by atomic nuclei in red giants.

R-process

The rapid capture of neutrons by atomic nuclei.

Electron

A negatively charged subatomic particle.

Proton

A positively charged subatomic particle.

Neutron

A subatomic particle with no charge.

Alpha Particle

A high-speed particle consisting of two protons and two neutrons.

Beta Particle

A high-speed electron.

Nuclear Reactions

Processes in which a nucleus either combines with another nucleus (through nuclear fusion) or splits into smaller nuclei (through nuclear fission).

Alpha Decay

The decay of an atom's nucleus by emitting an alpha particle, resulting in a change in the element.

Beta Decay

The decay of an atom's nucleus by emitting a beta particle, resulting in a change in the element.

Gamma Decay

The decay of an atom's nucleus by emitting gamma radiation, resulting in no change in the element.

Electron Capture

A decay process in which an electron is captured by a nucleus, resulting in a change in the element.

Positron Emission

A decay process in which a proton is transformed into a neutron, emitting a positron, resulting in a change in the element.

Elements in the Periodic Table

Chemical elements arranged based on increasing atomic number.

Atom

The basic unit of a chemical element.

Atomic Number

The number of protons in an atom, determining its identity.

Mass Number

The sum of protons and neutrons in an atom.

Neutron

A subatomic particle with no charge, found in the nucleus of an atom.

Atomos

The indivisible particles proposed by Leucippus and Democritus as the building blocks of matter.

Plum Pudding Model

A model proposed by J.J. Thomson, where electrons are surrounded by a volume of positive charge.

Atomic Nucleus

The dense center of an atom, discovered by Ernest Rutherford.

Proton

A positively charged particle found in the atomic nucleus.

Bohr Model of the Atom

A model proposed by Niels Bohr, where electrons orbit the nucleus in specific energy levels.

Neutron

An uncharged particle found in the atomic nucleus, discovered by James Chadwick.

Arrangement of Elements

The organization of elements in the periodic table based on increasing atomic number.

Synthetic Elements

Chemical elements formed in a laboratory through man-controlled processes.

Transuranium Elements

Elements heavier than Uranium, with atomic numbers greater than 92.

Polarity

The distribution of electrical charge over atoms joined by a chemical bond.

Chemical Bond

An electrical attraction between the nuclei and valence electrons of atoms.

Ionic Bond

A bond formed through the transfer of one or more valence electrons from one atom to another.

Covalent Bond

A bond formed through the sharing of an electron pair between atoms.

Geometrical Shape of Molecules

The three-dimensional arrangement of atoms and chemical bonds in a molecule.

VSEPR Model

The Valence Shell Electron Pair Repulsion model, which predicts the shape of molecules based on the repulsion between electron pairs.

Metallic Bonds

Bonds formed between metal atoms, where valence electrons are free to move throughout the structure.

Ions

Atoms or molecules with a net electric charge due to the loss or gain of one or more electrons.

Cations

Positively charged ions formed by losing electrons.

Electronegativity

The ability of an atom to attract electrons towards itself.

Intramolecular forces

The forces between atoms within a molecule.

Intermolecular forces (IMFA)

The forces of attraction between molecules.

London dispersion forces

The weakest intermolecular forces, present in nonpolar molecules and noble gases.

Dipole-dipole forces

Stronger than London dispersion forces, present in polar molecules due to uneven distribution of electrons.

Hydrogen bond

The strongest intermolecular force, occurs between hydrogen and electronegative atoms such as fluorine, oxygen, or nitrogen.

Ion-ion interaction

Interaction between oppositely charged ions, resulting in ionic compounds.

Solubility

The ability of a solid substance to dissolve in a given amount of solvent.

Miscibility

The ability of two liquids to mix in all proportions, creating a homogeneous mixture.

Boiling point

The temperature at which the vapor pressure and atmospheric pressure of a liquid substance are equal.

Melting point

The temperature at which a solid substance becomes a liquid.

Surface tension

The energy needed to increase the surface area of a liquid by a unit amount.

Viscosity

The resistance of a liquid to flow.

Vapor pressure

The pressure exerted by a substance in its gaseous state.

Volatility

The rate at which a substance vaporizes.

Biomolecules

Molecules that occur naturally in living organisms.

Saccharide

The unit structure of carbohydrates.

Monosaccharide

The simplest form of carbohydrates.

Monomer

A molecule that can react with other molecules to form larger polymers.

Peptide

A short chain of amino acids linked by peptide bonds.

Hormones

Special chemical messengers created in the endocrine gland.

Amino acids

Organic compounds that combine to form proteins.

Enzymes

Proteins that catalyze biochemical reactions.

Nucleotide

Made up of a nitrogen-containing base, five-carbon sugar, and a phosphate group.

Phospholipids

Molecules containing glycerol, two fatty acids, and a phosphate group.

Carbohydrates

Macromolecules composed of carbon, hydrogen, and oxygen, classified as simple or complex.

Lipids or Fats

Macromolecules composed of carbon, hydrogen, and oxygen, soluble in oil but insoluble in water.

Proteins

Macromolecules composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur and other metals.

Nucleic Acids

Biomolecules composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus, involved in genetic materials.

Chemical change

Occurs when new substances with different characteristics are formed.

Collision theory

States that reacting substances must collide with enough activation energy and in the correct orientation for a reaction to occur.

Chemical reaction

Bonds between particles are broken and reformed, creating one or more new substances.

Reactants

Substances that enter and are changed in a chemical reaction.

Products

Substances formed as a result of a chemical reaction.

Reaction rate

Measurement of the increase in product concentration or decrease in reactant concentration over time.

Activation energy

Minimum energy required for a reaction to take place.

Temperature

Hotness or coldness of a substance, affects the rate of a chemical reaction.

Concentration

Number of particles present in a given volume of solution, affects the rate of a chemical reaction.

Surface area and particle size

Measure of exposed area and affects the rate of a chemical reaction.

Catalyst

Substance that speeds up a chemical reaction without being consumed.

Heterogeneous catalyst

Catalyst and reactants are in different phases.

Homogeneous catalyst

Catalyst and reactants are dispersed in a single phase.

Biological catalyst

Enzymes that act as catalysts in biological reactions.

Law of Conservation of Mass

Mass is neither created nor destroyed in any chemical reaction.

Chemical equation

Describes a chemical change, with reactants on the left side and products on the right side.

Subscript

Shows the number of atoms of an element in a molecule.

Coefficient

Shows the number of molecules of a chemical in a reaction.

Matter cannot be created or destroyed.

Subscripts cannot be added, removed, or changed.

Coefficients can only go in front of chemical formulas.