Chp. 2 - Set #1

Flashcards covering the chemical basis of life, including matter, atomic structure, chemical bonding, and the properties of water and pH.

Matter

Anything that occupies space and has mass, composed of chemical elements.

Element

A substance that cannot be broken down to other substances by ordinary Chemical means.

Chemicals

Make up our body, bodies of other organisms, and the physical environment.

Trace Elements

Essential elements required by the body in minute quantities, such as iron, iodine, and Fluoride.

Fluoride

A trace element added to municipal water and dental products to help reduce tooth decay.

Compound

A substance consisting of $2$ or more different elements combined in a fixed ratio, such as Table Salt ($Sodium\,Chloride$).

Atom

The smallest unit of matter that still retains the properties of an element; historically described as "Indivisible."

Proton

A subatomic particle that is positively charged.

Electron

A subatomic particle that is negatively charged and rapidly orbits the exterior of the nucleus.

Neutron

A subatomic particle that is electrically neutral.

Nucleus

The central ball of an atom containing neutrons and protons.

Atomic Number

The number of protons in an element.

Mass number

The sum of protons and neutrons in an atom, often expressed in the unit of measurement "dalton."

Atomic mass

A value that is approximately equal to the mass number of an atom.

Isotopes

Variants of an element that have the same number of protons but a different number of neutrons, behaving identically in chemical reactions.

Radioactive Isotopes

An isotope whose nucleus decays spontaneously, giving off particles and energy.

Detriments of radioactive isotope Exposure

Damage of molecules in living cell like DNA & Abnormal chemical bonds formed from broken bonds

Benefits of Radioactive Isotopes

Useful in dating of fossils + biological research & medicine.

Electron shells

The specific energy levels at which electrons occur around the nucleus.

Chemical Bonds

Attractions that keep atoms close together, resulting from atoms sharing, donating, or receiving electrons to complete their outer shells.

Ion

An atom or molecule with an electrical charge resulting from the gain or loss of one or more electrons.

Ionic Bond

A bond formed by the attraction between two ions with opposite charges.

Covalent Bond

A strong chemical bond in which two atoms share one or more pairs of outer shell electrons.

Molecule

Two or more atoms held together by covalent bonds.

Double-Bond

A bond formed when atoms share two pairs of electrons, indicated by a pair of lines.

Valence

Also called bonding capacity, it is the number of additional atoms needed to fill an atom's outer shell.

Electronegativity

An atom's attraction for shared electrons in a covalent bond.

Nonpolar Covalent Bonds

Bonds in which electrons are shared equally between atoms.

Polar Covalent Bond

A bond involving the unequal sharing of electrons, where electrons are pulled closer to the more electronegative atom.

Polar Molecule

A molecule with an unequal distribution of charges, such as $H_2O$.

Hydrogen Bond

A type of bond where a positively charged region highlights a hydrogen atom's attraction to a nearby electronegative atom.

Cohesion

The tendency for molecules of the same kind to stick together, which is essential for transporting water and nutrients in plants.

Adhesion

The clinging of one substance to another, such as water clinging to the cell walls of plant veins.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid.

Heat

The total amount of energy associated with the movement of atoms and molecules in a body of matter.

Temperature

The measure of heat intensity, representing the average speed of molecules.

Evaporation

A process that moderates temperature as molecules with the greatest energy leave the liquid, cooling the surface left behind.

Solution

A liquid consisting of a uniform mixture of $2$ or more substances.

Solvent

The dissolving agent in a solution.

Solute

The substance that is dissolved in a solvent.

Aqueous Solution

A solution in which water acts as the solvent.

Hydrogen & Hydroxide Ions

Highly reactive ions formed for aqueous solution water molecules broken apart.

Acid

A compound that donates hydrogen ions ($H^+$) to solutions.

Base

A compound that accepts hydrogen ions and removes them from a solution.

Basic Solutions

Also called alkaline, with higher OH- concentration and lower H+ concentration

pH Scale

A scale describing how acidic or basic a solution is, ranging from $0$ (most acidic) to $14$ (most basic), with $7$ being neutral.

Buffers

Substances that minimize changes in pH by accepting $H^+$ when it is in excess and donating it when it is depleted.

Acid Precipitation

Rain, snow, or fog with a pH lower than $5.6$, resulting from sulfur and nitrous oxides reacting with water in the air.

Calcification

A process hindered by the lowering of seawater pH, which decreases the carbonate ions needed by corals and other organisms to produce calcium carbonate.

Chemical Reaction

The making and breaking of chemical bonds leading to changes in the composition of matter.

Reactants

The starting materials in a chemical reaction, shown on the left side of a chemical equation.

Products

The ending materials resulting from a chemical reaction, shown on the right side of a chemical equation.