Chapter 2: Chemical Basis of Life

Vocabulary flashcards covering core terms and definitions from Chapter 2: Chemical Basis of Life, including subatomic structure, atomic properties, chemical bonding, and molecular characteristics.

Matter

Anything that takes up space and has mass (weight), which is composed of elements.

Elements

Substances composed of chemically identical atoms that make up all matter and compounds.

Bulk elements

Elements required by the body in large amounts.

Trace elements

Elements required by the body in small amounts.

Ultratrace elements

Elements required by the body in very minute amounts.

Atom

The smallest particle of an element that has the properties of that element.

Electron

An extremely small subatomic particle with almost no weight that carries a single negative electrical charge ($e^-$) and is in constant motion around an atomic nucleus.

Proton

A relatively large atomic particle that carries a single positive electrical charge ($p^+$) and is found within an atomic nucleus.

Neutron

An atomic particle with about the same weight as a proton that is uncharged ($n^0$) and thus electrically neutral, found within an atomic nucleus.

Nucleus

The central part of an atom, composed of protons and neutrons, around which electrons move.

Atomic Number

The number of protons in the nucleus of one atom, which is unique to each element and equals the number of electrons in the atom.

Mass Number

The total number of protons plus the number of neutrons in one atom.

Atomic Weight

The average of mass numbers of the isotopes of an element.

Isotopes

Atoms with the same atomic numbers but different mass numbers, resulting from a different number of neutrons.

Molecule

A particle formed by the chemical union of two or more atoms.

Compound

A particle formed when two or more atoms of different elements chemically combine.

Molecular formulas

Formulas that depict the elements present and the exact number of each atom present in a molecule.

Electron shells

Regions of space circling the atomic nucleus occupied by electrons.

Ion

An electrically charged particle formed when an atom gains or loses one or more electrons to become stable.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Ionic Bonds

Chemical bonds formed by the attraction between a cation and an anion when electrons are transferred from one atom to another.

Covalent Bonds

Chemical bonds formed when atoms share electrons.

Structural formulas

Formulas that show how atoms bond and are arranged in various molecules.

Polar Molecules

A molecule with a slightly negative end and a slightly positive end, resulting from unequal sharing of electrons in covalent bonds.

Hydrogen Bonds

A weak attraction between the positive end of one polar molecule and the negative end of another polar molecule.