Introduction to Biological Chemistry, Chemical Bonding, and Water Properties

Flashcards covering key terms and concepts from Chapter 1 through Chapter 8, including atomic metrics, electron shell rules, bond types, reaction states, and water characteristics.

Valence Electrons

The number of electrons present in the outermost electron shell of an atom.

Valence

The number of unfulfilled electron spaces remaining in an atom's outermost shell, which determines its chemical reactivity.

Noble Gases

Nonreactive, highly stable elements located in the rightmost column of the periodic table that possess a valence of $0$.

Atomic Number

The number of protons in an atom's nucleus, which dictates the fundamental identity of the element.

Atomic Mass

The combined weight of an atom calculated by adding its number of protons and neutrons, expressed in atomic units.

Covalent Bond

The strongest chemical interaction in biology, defined as two atoms sharing one or more pairs of electrons.

Electronegativity

The strong attractive force an atom exerts to pull shared electrons toward itself within a chemical bond.

Polarity

An overall difference in electrical charge across a molecule caused by unequal electron sharing.

Ionic Bond

A chemical interaction formed between two atoms due to a full electrical charge difference, typically resulting from electron transfer.

Ionization

The process by which an atom gains or loses electrons to acquire a net electrical charge.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Hydrogen Bond

A weak attraction between adjacent polar molecules caused by partial electrical charge differences.

Van der Waals Interactions

Weak biological interactions resulting either from complementary molecular shapes fitting together or from spontaneous, rapid changes in charge.

Reactants

The starting materials that participate in and are consumed by a chemical reaction.

Products

The ending substances created as a result of a completed chemical reaction.

Chemical Equilibrium

The state of a chemical reaction where forward and reverse reaction rates balance, producing zero net overall change in substance amounts.

Cohesion

The property of identical molecules sticking to one another, such as water molecules held together by hydrogen bonds.

Evapotranspiration

The process in plants where solar evaporation at the leaves physically pulls cohesive columns of water upward through xylem tubes from the roots.

Maximum Water Density

The physical state achieved by liquid water at $4\,^\circ\text{C}$, above which it expands into a less dense crystalline structure as ice at $0\,^\circ\text{C}$.