Grade Biology Exam 1

Study of matter & the energy that causes matter to do things, allowing the matter to make up all things (living & nonliving) that exist in the natural world

Anything that has mass & occupies space; composed of elements

Pure form of matter that cannot be broken down to a simpler form; made up of atoms

Smallest unit of any element that still retains the physical & chemical properties of that element; smallest units of matter that can take part in chemical reactions

Central core of an atom, made of protons & neutrons tightly bound together; electrons circle the nucleus

Positively charged particles (equal to number of electrons in atom)

Neutral particles

Smaller, negatively charged particles that orbit the nucleus; occupy one or more spherical clouds around the nucleus called shells; first shell can hold 2 electrons, second shell up to 8, third shell also 8

Number of protons in the nucleus of an atom

Amount fairly close to the total # of neutrons & protons

Although all atoms of a particular element have the same amount of protons, the # of neutrons can vary slightly from atom to atom, so atoms with fewer or more than the usual # of neutrons for an element are this; they will have the same atomic # but a different atomic mass (total of protons & neutrons added together) than other atoms of the same element as them

Many isotopes are unstable, they give off energy in the form of radiation until they reach a more stable state; can be used to know how old fossils are

Consists of a stable association between 2 or more atoms

The capacity to do "work", capacity to cause some change in matter; joining atoms & breaking up molecules both require energy & are "work"

Stored energy that is not performing any work at the moment but has potential to make things happen