Basics of Chemistry

Matter

Anything that has mass and takes up space.

Elements

The basic building blocks of matter.

Atoms

The smallest units of an element.

Molecules

Groups of atoms bonded together.

Four primary elements in the human body

Nitrogen, hydrogen, carbon, and oxygen.

Atomic number

The number of protons in the atomic nucleus.

Mass number

The total number of protons and neutrons in the nucleus.

Isotopes

Forms of an element that differ in the number of neutrons.

Radioactivity

The spontaneous decay of an unstable nucleus, giving off particles and energy.

Valence electrons

Electrons occupying the outermost shell, determining chemical behavior.

Ionic bonds

Results from the transfer of electrons between atoms, forming charged ions.

Covalent bonds

Formed when atoms share electrons to achieve stable outer shells.

Hydrogen bonds

Weak attractions between polar molecules, particularly water.

Cohesion

Molecules attracted to one another, as seen in water.

Adhesion

Molecules attracted to other molecules or ions.

pH scale

Measures the strength of acids and bases based on hydrogen ion concentration.

Buffers

Substances that minimize changes in concentrations of protons and hydroxide ions in a solution.

Aqueous solution

A solution where water is the solvent.

Solute

The substance that is dissolved in a solution.

Acids

Substances that dissociate and release hydrogen ions (H+).

Bases

Substances that take up protons or release hydroxide ions (OH-).