bio

Matter

Anything that takes up space and has mass, made of elements and compounds.

Atom

The smallest unit of matter that retains properties of an element.

Protons

Subatomic particles with a positive charge (+) found in the nucleus.

Neutrons

Subatomic particles with no charge found in the nucleus.

Electrons

Subatomic particles with a negative charge (-) that form a cloud around the nucleus.

Atomic number

The number of protons in an element.

Atomic mass

The sum of protons and neutrons in an atom.

Isotopes

Atoms with the same number of protons but different numbers of neutrons.

Radioactive isotopes

Isotopes whose nucleus decays, emitting particles or energy, useful for medical research.

Electron shells

Energy levels surrounding the nucleus where electrons reside.

First electron shell

Holds a maximum of 2 electrons.

Second electron shell

Holds a maximum of 8 electrons.

Valence shell

The outermost shell of an electron that determines bonding behavior.

Energy levels

Higher energy levels are associated with electrons further from the nucleus.

Covalent bonds

Bonds formed when atoms share valence electrons.

Single bond

A bond in which 1 pair of electrons is shared between two atoms.

Double bond

A bond in which 2 pairs of electrons are shared between two atoms.

Nonpolar covalent bond

A bond in which electrons are shared equally between atoms.

Polar covalent bond

A bond where electrons are shared unequally, resulting in partial charges.

Ionic bonds

Bonds formed when electrons are transferred from one atom to another.

Cation

A positively charged ion that has lost one or more electrons.

Anion

A negatively charged ion that has gained one or more electrons.

Hydrogen bonds

Weak attractions between partially positive hydrogen atoms and electronegative atoms.

Van der Waals interactions

Weak attractions between molecules due to transient charges.

Reactants

Starting materials in a chemical reaction.

Products

The resulting materials formed from a chemical reaction.

Photosynthesis

The process by which sunlight converts CO2 and H2O into glucose and O2.

Chemical equilibrium

A state where the rate of the forward reaction equals the rate of the reverse reaction.

Polar molecule

A molecule with partial charges due to differences in electronegativity.

Cohesion

The tendency of water molecules to stick together due to hydrogen bonding.

Adhesion

The tendency of water molecules to stick to other substances.

High specific heat

The ability of water to absorb and release heat with only small temperature changes.

Heat of vaporization

The amount of energy needed to convert water from liquid to gas.

Evaporative cooling

The cooling effect seen when water evaporates.

Ice floats

Ice expands upon freezing due to the formation of a crystalline lattice structure.

Solution

A homogeneous mixture formed when a solute is dissolved in a solvent.

Solvent

The dissolving agent in a solution.

Solute

The substance that is dissolved in a solution.

Aqueous solution

A solution where water is the solvent.

Hydrophilic

Substances that are attracted to water (polar/ionic substances).

Hydrophobic

Substances that repel water (nonpolar substances).

pH scale

A measure of the concentration of H+ ions in a solution.

Acid

A substance that increases the concentration of H+ in a solution.

Base

A substance that reduces the concentration of H+ in a solution.

Buffer

A substance that minimizes changes in H+ and OH- concentrations in a solution.

Organic chemistry

The study of carbon-containing compounds.

Hydrocarbons

Molecules that consist only of carbon and hydrogen.

Isomers

Compounds with the same molecular formula but different arrangements of atoms.

Functional groups

Groups of atoms that determine the properties and behaviors of organic compounds.

ATP

Adenosine triphosphate, the primary energy molecule in cells.

Energy transfer in ATP

Energy is released when the phosphate bonds in ATP are broken.