The Chemical Basis of Life I: Atoms, Molecules and Water

These flashcards cover crucial vocabulary and definitions from the lecture on the chemical basis of life, focusing on atoms, molecules, and water.

Atom

The basic unit of a chemical element, composed of protons, neutrons, and electrons.

Proton

A positively charged particle found in the nucleus of an atom.

Neutron

A neutral particle found in the nucleus of an atom.

Electron

A negatively charged particle that orbits the nucleus of an atom.

Isotope

Forms of an element with different numbers of neutrons.

Valence Shell

The outermost occupied shell of an atom that determines its chemical properties.

Covalent Bond

A bond formed when atoms share unpaired valence electrons.

Ionic Bond

A bond that occurs when electrons are transferred from one atom to another, creating ions.

Hydrogen Bond

Weak attractions between partially charged molecules, such as between water molecules.

Polar Covalent Bond

A bond where electrons are shared unequally, leading to partial charges on the atoms.

Hydrophobic

Describes molecules that do not interact well with water; often nonpolar compounds.

Hydrophilic

Describes molecules that readily interact with water; often ionic or polar.

pH Scale

A measure of the acidity or basicity of a solution, ranging from 0 (acidic) to 14 (basic).

Acid

A substance that donates protons (H+) in a solution.

Base

A substance that accepts protons (H+) or donates hydroxide ions (OH-) in a solution.