Matter, Atomic Bonding, and the Hydrologic Cycle

Comprehensive vocabulary flashcards covering atomic structure, chemical bonding, radioactivity, water chemistry, and the hydrologic cycle.

System

A set of interacting components connected in a way that a change in one part of the system affects one or more parts of that system.

Matter

Anything that takes up space.

Mass

A measurement of how much matter an object has.

Weight

The force resulting from the action of gravity on mass, represented by the formula $W = mg$.

Atom

The fundamental building blocks of matter.

Element

A substance composed of atoms that cannot be broken down into smaller, simpler, and different components.

Molecule

Particles that contain more than one atom.

Compound

Molecules that contain more than one element.

Protons

Subatomic particles located inside the nuclei of atoms that carry a positive electric charge and determine an element's atomic number.

Nucleus

The positively charged central core of an atom composed of protons and neutrons.

Neutrons

Subatomic particles that do not contain an electric charge, stabilize the nucleus, and are found in all atomic nuclei except ordinary hydrogen.

Electrons

Subatomic particles carrying a negative electric charge that are located in orbitals surrounding the nucleus.

Orbitals

Electron clouds that extend at different distances from the nucleus and influence an atom's chemical behavior.

Atomic number

The total number of protons located in the nucleus of an element.

Mass number

The total number of protons and neutrons found in an element.

Isotopes

Atoms of the same element containing different numbers of neutrons, resulting in different atomic masses.

Octet rule

The principle stating that an atom's first orbital can hold up to $2$ electrons, while subsequent orbitals can hold up to $8$ electrons.

Covalent bonds

Bonds formed between elements that create compounds by sharing electrons.

Ionic bonds

Chemical bonds formed by transferring electrons from one element to another, holding the resulting cations and anions together via charge imbalance.

Hydrogen bonds

Chemical bonds formed when a slightly positive ($\delta^+$) hydrogen atom covalently bonded to one atom is attracted to a slightly negative ($\delta^-$) atom on a different molecule.

Metallic bonds

Bonds between metal atoms that lose their outermost electrons to become cations, held together by high electromagnetic energy from a surrounding floating pool of electrons.

Radioactive decay

The spontaneous release of material from the nucleus of an unstable isotope, changing it into a different element (such as Uranium-235 decaying to Thorium-231).

Half-life

The time it takes for one half of the original radioactive parent atoms to decay.

Carbon dating

A technique used to calculate how long an organism has been dead based on the proportion of radioactive Carbon-14 that has decayed into Nitrogen-14.

High heat capacity

The property that allows water to absorb large amounts of heat before increasing in temperature, enabling organisms to buffer and regulate body temperature.

Universal solvent

A property of water referring to its capability to dissolve more polar substances than any other liquid due to its polar nature and partial charges ($\delta^+$ and $\delta^-$).

Cohesion

The attraction between water molecules due to hydrogen bonding, allowing water to form droplets on dry surfaces.

Surface tension

The capacity of a substance to resist rupture under tension stress, made possible by water's cohesive forces.

Adhesion

The attraction between water molecules and the molecules of other substances or objects.

Capillary action

The upward movement of water through narrow spaces or tubes defying gravity, utilizing adhesion and cohesion.

Evaporation

The process that turns liquid water into gas when molecules break their hydrogen bonds, accounting for $90\%$ of the moisture in Earth's atmosphere.

Stomata

Microscopic pores on the undersides of leaves regulated by two guard cells that swell and shrink to control gas exchange and water release.

Transpiration

The biological process in which plants draw water from the soil and expel it into the atmosphere via leaf stomata.

Evapotranspiration

The combined processes by which water moves from Earth's surface into the atmosphere.

Condensation

The reverse of evaporation, occurring when warm moist air rises, cools, and forms water droplets or ice crystals around condensation nuclei to produce clouds.

Precipitation

Water released from clouds in the form of rain, freezing rain, sleet, snow, or hail; the primary delivery mechanism of water to Earth.

Frontal rainfall

A form of precipitation that occurs when air fronts with differing temperatures and moisture levels converge.

Convective rainfall

Intense rainfall resulting from localized surface heating that causes hot, moist air to rise, condense, and form storm clouds.

Orographic rainfall

Precipitation formed when moist air is forced over mountains, cooling and condensing into rain clouds on the windward side.

Surface water runoff

Water that flows across the Earth's surface toward lower elevations, forming channels starting as rills and rivulets.

Tributaries

Smaller streams and rivers that flow into and feed larger rivers.

Watershed

A land area drained by a river and its tributaries, also known as a catchment or rain basin.

Floodplain

A fertile flat area adjacent to a river that temporarily stores excess water during storm events and is subject to frequent flooding.

Groundwater

Water located beneath the Earth's surface that accounts for up to $97\%$ of available fresh water.

Soil moisture

Water contained within the unsaturated zone above groundwater.

Aquifers

Rock formations or sediments containing significant amounts of stored groundwater within their pore spaces.