BIO

Element

A fundamental substance that contains one kind of atom, determined by the number of protons.

Atom

The basic unit of matter composed of three subatomic particles: protons, neutrons, and electrons.

Proton

Positively charged subatomic particle found in the nucleus of an atom.

Neutron

Subatomic particle located in an atom's nucleus that has no charge.

Electron

Negatively charged subatomic particle that orbits around an atom's nucleus.

Atomic number

A unique number assigned to each element that equals the number of protons in its atom.

Isotope

Atoms of a particular element that differ in the number of neutrons.

Valence shell

The outermost electron shell of an atom, where electrons participate in chemical reactions.

Electronegativity

The attractive force that an atom's nucleus exerts on its electrons.

Chemical bond

An attractive force that links atoms together to form molecules and compounds.

Covalent bond

A chemical bond formed when two atoms share pairs of electrons.

Ionic bond

A bond formed between ions of opposite charges.

Ion

Charged particles formed when an atom gains or loses electrons.

Cation

Positively charged ion that forms when an atom loses electrons.

Anion

Negatively charged ion that forms when an atom gains electrons.

Hydrogen bond

A weak bond formed when a hydrogen atom is attracted to a partial negative charge in another molecule.

Van der Waals interactions

Weak attractions between molecules or parts of molecules that result from transient local partial charges.

Molecule

A group of two or more atoms bonded together.

Compound

A molecule formed from at least two different elements.

Kinetic energy

The energy of movement, including thermal and electromagnetic energy.

Potential energy

Stored energy, which includes chemical energy.

Chemical reaction

A process where atoms combine or change their bonding partners.

Reactants

The starting materials in a chemical reaction.

Products

The substances formed as a result of a chemical reaction.

Hydrolysis reaction

A reaction that includes water as a reactant and breaks down complex molecules into simpler ones.

Condensation reaction

A reaction that combines simpler molecules to form more complex molecules, releasing water as a product.

Activation energy (Ea)

The energy required to start a chemical reaction.

Reaction rate

The speed at which products are formed in a reaction, influenced by various factors such as temperature and concentration.

Equilibrium

A state in which the rates of forward and reverse chemical reactions are equal.

Gibbs free energy (ΔG)

The change in the total amount of energy available to do work in a chemical reaction.

Exergonic

A reaction that releases energy, resulting in a negative ΔG.

Endergonic

A reaction that requires energy input, resulting in a positive ΔG.

Specific heat

The amount of heat needed to change the temperature of a substance.

Heat of vaporization

The amount of heat required to convert a liquid into vapor.

Cohesion

The attraction between water molecules that generates surface tension.

Adhesion

The attraction between water molecules and different substances.

Solvent

A substance that dissolves a solute to form a solution.

Hydrophilic

Substances that dissolve easily in water.

Hydrophobic

Substances that do not dissolve easily in water.

Amphipathic

Molecules that have both hydrophilic and hydrophobic regions.

pH

A measure of the acidity or alkalinity of a solution based on hydrogen ion concentration.

Acids

Substances that decrease the pH of a solution by increasing hydrogen ion concentration.

Bases

Substances that increase the pH of a solution by decreasing hydrogen ion concentration.

Buffer

A substance that minimizes changes in pH by adding or removing hydrogen or hydroxide ions.

Functional groups

Specific groups of atoms within molecules that determine the properties and reactions of those molecules.

Organic chemistry

The study of carbon-containing compounds and their properties.