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30 terms

Elements and the periodic table

Prentice Hall Science Explorer Chemical Building Blocks Chapter 3
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nucleus
an atom's central region, which is made up of protons and neutrons
proton
a subatomic particle that has a positive charge and that is found in the nucleus of an atom
neutron
a subatomic particle that has no charge and that is found in the nucleus of an atom
electron
negatively charged particle; located outside the atomic nucleus
atomic number
the number of protons in the nucleus of an atom
isotope
an atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass)
mass number
the sum of the number of neutrons and protons in an atomic nucleus
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
atomic mass
the average mass of all the isotopes of an element
periodic table
a tabular arrangement of the chemical elements according to atomic number as based on the periodic law
chemical symbol
a one or two letter representation of an element
period
a horizontal row of elements in the periodic table
group
Vertical column of elements in the periodic table
metal
a class of elements characterized by physical properties that include shininess, malleability, ductility, and conductivity
malleable
can be bent and pounded into various shapes
ductile
Capable of being drawn out, as into wire or a thread.
conductivity
the ability of an object to transfer heat or electricity to another object
reactivity
the ease and speed with which an element combines, or reacts, with other elements and compounds
corrosion
the gradual wearing away of a metal element due to a chemical reaction
alkali metal
an element in group 1 of the periodic table
alkaline earth metals
The name of the family of elements in Group 2.
transition metal
An element in group 3 through 12 of the periodic table
alloy
a mixture of two or more elements, one of which is a metal
particle accelerator
a machine that moves atomic nuclei at higher and higher speeds until they crash into one another, sometimes forming heavier elements
nonmetal
An element that lacks most of the properties of metals
diatomic molecule
a molecule consisting of two atoms
halogen
an element found in group 17 of the periodic table
noble gas
one of the elements of Group 18 of the periodic table (helium, neon, argon, krypton, xenon, and radon); are unreactive
metalloid
an element that has some characteristics of metals and some characteristics of nonmetals
semiconductor
an element that can conduct electricity under some conditions