Basic Chemistry

Chemistry

is the basis for how the body transforms and uses energy and for how our cells use molecules such as carbohydrates, lipids, proteins, and nucleic acids

Matter

is anything that occupies space and has mass

Weight

is a measure of gravity pulling on mass

Chemistry

studies the nature of matter—how its building blocks are put together and how they interact

Matter

exists in solid, liquid, and gaseous states, all of which are found in the human body

Solids

such as bones and teeth, have a definite shape and volume

Liquids

have a definite volume, but they conform to the shape of their container

Gases

have neither a definite shape nor a definite volume

Matter

may be changed both physically and chemically

Physical changes

change that do not alter the basic nature of a substance

Chemical changes

do alter the composition of the substance—often substantially

energy

the ability to do work or to put matter into motion

kinetic energy

when energy is actually doing work (moving objects)

potential energy

When energy is inactive or stored (as in the batteries of an unused toy)

Chemical energy

is stored in the bonds of chemical substances

Electrical energy

results from the movement of charged particles

Mechanical energy

is energy directly involved in moving matter

Radiant energy

travels in waves; that is, it is the energy of the electromagnetic spectrum, which includes X rays, infrared radiation (heat energy), visible light, radio, and ultraviolet (UV) waves

elements

unique substances that cannot be broken down into simpler substances by ordinary chemical methods

periodic table

A complete listing of the elements

atoms

Each element is composed of very similar parti- 2
cles, or building blocks, called _____.

atomic symbol

We designate each element by a one- or two-letter shorthand name called an _____.

subatomic particles

Atoms, although indescribably small, are clusters of even smaller components called _____.

Protons (p+)

have a positive charge

neutrons (n0)

are uncharged or neutral

electrons (e2)

bear a negative charge equal in strength to the positive
charge of the protons

planetary model

portrays the atom as a miniature solar system

orbital model

depicts the general location of electrons outside the nucleus as a haze of negative charge

atomic number

A number that is given to each element, that is equal to the number of protons its atoms contain

atomic mass number (or just mass number)

is the sum of the masses of all the protons and neutrons contained in its nucleus

isotopes

The atoms of almost all elements exhibit two or more structural variations; these varieties are called _____.

radioisotopes

The heavier isotopes of certain atoms are unstable and tend to release energy in order to become more stable; such isotopes are called _____.

radioactivity

process of spontaneous atomic decay

molecules

When two or more atoms combine chemically, _____ are formed

compound

When two or more different atoms bind together to form a molecule, the molecule is more specifically referred to as a molecule of a _____.