Glossary of
Terms
1st Weeks
Allotropes -
Different molecular structures of the same element
Atom -
The smallest particle of an element that still retains the properties of the element
Atomic number-
Number of protons in an atom's nucleus
Average atomic
mass-
Weighted-average mass of an element's isotopes according to their natural abundance
Bias -
occurs when a scientist's expectations change how the results of an experiment are viewed
Boiling point -
the temperature at which the pressure of the vapor of a liquid is equal to the external pressure
acting on the surface of the liquid
states that the volume and pressure of a gas are related, such that if the temperature of a gas
remains constant, an increase in volume causes a proportional decrease in the pressure
ability of a fluid, which include liquids and gases, to exert an upward force on an object
immersed in it
states that the temperature and volume of a gas are related such that, if the pressure is
constant, an increase in temperature will produce a proportionate increase in the volume
change of one substance into a new substance
Boyle's law Buoyancy Charles's law Chemical change Chemical property Colloid -
any characteristic of a substance, such as flammability, that can be observed that produces a
new substance
heterogeneous mixture whose particles never settle
Compound -
substance in which the atoms of two or more elements are combined in a fixed proportion
Constant -
in an experiment, a variable that does not change
Control -
standard used for comparison of test results in an experiment
Density -
mass per unit volume of a material
Dependent variable -
factor that changes as a result of changes in the other variables
Diatomic molecule -
A molecule that consists of two atoms of the same element
Diffusion –
spreading of particles throughout a given volume until they are uniformly distributed
Distillation Ductile
process that can separate two substances in a mixture by evaporating a liquid and
recompensing its vapor
- Property of metals and alloys that allows them to be drawn into wires
Electron
- Particle with an electric charge of 1–, surrounds the nucleus of an atom
Electron cloud -
Area around the nucleus of an atom where the atom's electrons are most likely to be
found
Electron dot
diagram -
Uses the symbol for an element and dots representing the number of electrons in the
element's outer energy level
Element -
substance with atoms that are all alike
Experiment Graph -
organized procedure for testing a hypothesis; tests the effect of one thing on another under
controlled conditions
visual display of information or data
Group –
Vertical column in the periodic table
Heat of fusion -
amount of energy required to change a substance from the solid phase to the liquid phase
Heat of vaporization - the amount of energy required for a liquid at its boiling point to become a gas
Heterogeneous
mixture
substance in which its different components are easily distinguished
Homogeneous
mixture -
substance containing two or more components that are blended uniformly so that individual
components are indistinguishable with a microscope
Hypothesis -
possible explanation for a problem using what is known and what is observed
Independent variable
factor that, as it changes, affects the measure of another variable
Isotope -
Atom of an element that has a specific number of neutrons
Kinetic theory Law of conservation
of mass -
explanation of the behavior of particles in gases; states that matter is made of constantly
moving particles that collide without losing energy
states that the mass of all substances present before a chemical change equals the mass of all
the substances remaining after the change
Malleable -
Property of metals and alloys that allows them to be hammered or rolled into thin sheets
Mass -
amount of matter in an object
Mass number –
Sum of the number of protons and neutrons in an atom's nucleus
Matter -
anything that takes up space and has mass
Melting point -
temperature at which a solid begins to liquefy
Metal -
Element that typically is shiny, malleable, ductile, and a good conductor of heat and electricity
Metallic bonding
- Occurs because some electrons move freely among a metal's positively charged ions, explains
properties such as ductility and the ability to conduct electricity
Element that shares some properties with metals and some with nonmetals
Metalloid Model -
can be used to represent an idea, object, or event that is too big, too small, too complex, or too
dangerous to observe or test directly
Neutron –
Electrically neutral particle inside the nucleus of an atom
Nonmetal -
element that usually is a gas or brittle solid at room temperature, is not malleable or ductile, is a
poor conductor of heat and electricity, and typically is not shiny
Nucleus -
The small, positively charged center of an atom, contains protons and neutrons
Pascal -
SI unit of pressure
Period –
Horizontal row in the periodic table
Periodic table -
Organized list of all known elements that are arranged by increasing atomic number
and by changes in chemical and physical properties
Physical change -
Pressure -
any change in size, shape, or state of matter in which the identity of the substance remains the
same
any characteristic of a material, such as size or shape that can be observed without changing
the identity of the material
matter with enough energy to overcome the attractive forces within its atoms, composed of
positively and negatively charged particles
amount of force exerted per unit area; SI unit is the Pascal (Pa)
Proton –
Particle in the nucleus with an electric charge of 1+
Quark –
Particle of matter that makes up protons and neutrons
Radioactive element
Element, such as radium, whose nucleus breaks down and emits particles and energy
Scientific law -
statement about what happens in nature that seems to be true all the time; does not explain
why or how something happens
pattern of investigation procedures that can include stating a problem, forming a hypothesis,
researching and gathering information, testing a hypothesis, analyzing data, and drawing
conclusions
Material that conducts an electric current under certain conditions
Physical property Plasma -
Scientific methods -
Semiconductor SI Society Solution -
International System of Units—the improved, universally accepted version of the metric system
that is based on multiples of ten and includes the meter (m), liter (L), and kilogram (kg)
group of people that share similar values and beliefs
Standard -
homogenous mixture, remains constantly and uniformly mixed and has particles that are so
small they cannot be seen with a microscope
exact, agreed-upon quantity used for comparison
Sublimation -
the process of a solid changing directly to a vapor without forming a liquid
Substance -
element or compound that cannot be broken down into simpler components without losing the
properties of the original substance
heterogeneous mixture containing a liquid, and in which visible particles slowly settle due to
gravity
application of science to benefit people
Suspension Technology Theory Thermal expansion Tran’s uranium
elements -
explanation of things or events based on knowledge gained from many observations and
investigations
increase in the volume of a substance when the temperature is increased
Elements having more than 92 protons, all of which are synthetic and unstable
Transition elements Tyndall effect Variable -
Elements in groups 3 through 12 of the periodic table; occur in nature as uncombined elements
and include the iron triad and coinage metals
tendency for a beam of light to scatter as it passes through a colloid
Viscosity –
quantity that can have more than a single value, can cause a change in the results of an
experiment
a fluid's resistance to flowing
Volume -
amount of space occupied by an object