chemistry in biology

Atoms

Atoms

Smallest unit of matter with element properties.

Protons

Positively charged particles in an atom.

Neutrons

Neutral particles found in atomic nucleus.

Electrons

Negatively charged particles surrounding the nucleus.

Valence electrons

Electrons in the outermost shell of an atom.

Ions

Charged atoms formed by electron loss or gain.

Cations

Positive ions formed by losing electrons.

Anions

Negative ions formed by gaining electrons.

Compound

Two or more different atoms bonded together.

Molecule

One or more atoms bonded together.

Molecular formulas

Representations showing number of atoms in molecules.

Ionic bond

Bond formed by transfer of electrons between atoms.

Covalent bond

Bond formed by sharing electrons between nonmetals.

Nonpolar bonds

Covalent bonds with equal electron sharing.

Polar bonds

Covalent bonds with unequal electron sharing.

Hydrogen bonds

Attractive forces between polar molecules.

Cohesion

Attraction between water molecules.

Surface tension

Liquid's resistance to external force due to cohesion.

Adhesion

Attraction of water to other polar molecules.

Capillary action

Liquid's ascent through narrow spaces due to adhesion.

Heat capacity

Water's ability to absorb energy without temperature change.

Specific heat

Heat needed to raise water's temperature by 1°C.

Universal solvent

Water's ability to dissolve many substances.

Hydrophilic

Substances that are attracted to water.

Hydrophobic

Substances that repel water.

Solutions

Homogeneous mixtures of solute and solvent.

Suspensions

Mixtures that do not dissolve and settle out.

Solvent

Substance that dissolves the solute.

Solute

Substance that is dissolved in a solution.

pH scale

Measures acidity or alkalinity of a solution.

Acids

Substances with pH below 7, produce H+ ions.

Bases

Substances with pH above 7, produce OH- ions.

Reactants

Substances that undergo a chemical reaction.

Products

Substances formed as a result of a reaction.

Exothermic reaction

Chemical reaction that releases heat.

Endothermic reaction

Chemical reaction that absorbs heat.