Biological Chemistry: Matter and Energy

Vocabulary practice flashcards covering basic chemical principles, subatomic particles, chemical bonds, and energy dynamics in biological systems.

Matter

Any substance that occupies space and has mass.

Element

A unique form of matter with specific chemical and physical properties that cannot break down into smaller substances by ordinary chemical reactions.

Atomic number

The top number on the periodic table representing the number of protons, which makes an element unique.

Atomic mass

The mass number representing the combined total number of protons and neutrons in an atom.

Protons

Subatomic particles located in the nucleus that possess a positive charge.

Electrons

Subatomic particles located in orbitals or clouds around the nucleus that possess a negative charge.

Neutrons

Subatomic particles located in the nucleus that have a neutral charge.

Bohr model

An atomic model developed by Niels Bohr in $1913$ in which electrons exist within principal shells depicted as concentric circles.

Valence

A measure of the outer shell electrons of an atom.

Kinetic energy

The energy possessed by objects or chemicals in motion.

Potential energy

The stored energy available to do work based on location and structure.

Chemical energy

A specific type of structural potential energy in cells that is released when chemical bonds break.

Ionic bond

A type of chemical bond formed when electrons are completely transferred from one atom to another, giving the resulting atoms full charges.

Covalent bond

A chemical bond formed when electrons are shared between atoms or elements.

Electronegativity

An inherent property of elements that measures how greedy an atom is for electrons.

Nonpolar covalent bond

A covalent bond formed when electrons are shared equally between atoms, resulting in no dipole or polarity.

Polar covalent bond

A covalent bond formed when electrons are shared unequally because one element holds onto the electrons tighter than the other.

Exergonic reactions

Chemical reactions with a negative change in free energy where energy leaves the system, allowing them to occur spontaneously.

Endergonic reactions

Chemical reactions with a positive change in free energy that require energy input from outside the system and are non-spontaneous.

Activation energy

The initial amount of energy input required by both exergonic and endergonic reactions to reach a high-energy transition state.