73 terms

Physics Ch. 2


Terms in this set (...)

anything that has mass and takes up space; anything having inertia
matter's unique property of resisting any change in its present state of motion
matter in motion will remain in motion
matter at rest will stay at rest
Newton's definition of inertia
represents how much inertia an object has, or how much force is required to change the object's state of motion
represents the amount of force the earth's gravity exerts on an object's mass
the ratio of an object's mass to its volume
ρ = m/v
equation for density
1 cm³
what 1 mL is equal to
specific gravity
the ratio of a given sample's density to a standard density
the standard for liquids and solids
hydrogen gas
the standard for gases
sp. gr. = ρ of sample/ρ of standard
equation for specific gravity
a chemical combination of two or more atoms
elemental molecule
if the elements are the same, the molecule is called __
what a molecule is called if the atoms in a single molecule are different elements
pure substance
a substance containing only one kind of atom or molecule
physical combinations of two or more elements or compounds
what a mixture is called if the particles of each substance are uniformly distributed throughout the mixture on a molecule-by-molecule basis
what a mixture is called if the mixture settles into layers of different particles or has large clumps of molecules
type of matter that has a definite shape and volume
type of matter that has a definite volume and an indefinite shape
type of matter that does not have a definite volume or shape
type of matter that is a highly ionized gas
the basic building block of all matter
a collection of particles fixed at the center of an atom
proton (p⁺)
a positively charged particle that gives the atom its identity as an element
atomic number
the number of protons in a given element; determines the atom's type
neutron (n⁰)
the largest atomic particle; has a neutral charge
mass number
states the sum of the number of protons and neutrons in the nucleus
atoms with the same atomic number but differing mass numbers
atomic mass
the general mass of an element
atomic mass units
what atomic mass is measured in
electron (e⁻)
a negatively charged particle in the atom
a charged particle that resulted from the loss or gain of electrons
a negative ion
a positive ion
any substance that cannot be broken down by chemical means into a simpler substance
rows on the periodic table
columns on the periodic table
valence electrons
electrons in the outermost electron layer
E = mc²
Einstein's equation relating mass and energy
the tiny particles that make up light
1. mass gain
2. nuclear mass defect
the two implications of E = mc²
energy increases, mass increases
energy decreases, mass decreases
the relationship between mass and energy
subatomic particles
particles that are smaller than an atom
elementary particles
defined as having no components, no building blocks, and no smaller parts
of protons, neutrons, and electrons, the only one that is considered an elementary particle
smaller particles that make up protons and neutrons
any substance believed to contain quarks
hadrons containing two quarks
hadrons containing three quarks
believed to bind the quarks together
subatomic particles that do not contain any quarks
true or false: electrons do not contain quarks
a particle that has a mass of virtually zero and travels virtually at the speed of light
a positively charged electron
gamma radiation
an invisible, highly penetrating type of electromagnetic radiation that is extremely dangerous to humans
pair production
the process of gamma radiation passing through a heavy material, causing a photon to vanish and an electron and a positron to suddenly appear
electromagnetic radiation
any type of emitted energy
particles that have the exact same characteristics, but opposite charges
1. electron/positron
2. proton/antiproton
3. neutron/antineutron
the three main groups of antiparticles
true or false: antiparticles can exist in their opposite particles' presence
what particles like the positron, the antiproton, and the antineutron are sometimes called
occurs when a positron and electron collide and convert their combined masses into a form of energy; opposite of pair production
a region of high likelihood for finding an electron as it travels around the nucleus
electron capture
when a proton absorbs an electron as it is orbiting the nucleus; produces a radiated neutrino
heavy atoms
atoms with a neutron to proton ratio greater than 1:1
radioactive decay
the process that occurs when heavy atoms release energy to become more stable
alpha decay (α decay)
type of decay in which a nucleus emits a helium atom (two protons and two neutrons); perceived as a gentle warmth
two fewer
in alpha decay, the heavy element's identity is changed to an element with __ __ protons
beta decay (β decay)
type of decay in which a neutron is changed into a proton, emitting an electron
one greater
in beta decay, the heavy element's atomic number becomes __ proton __
defined as the time required for half a radioactive substance's mass to decay into something else