Science: Ch. 3 Elements & the Periodic Table
oxygen family
Group 16-contains three nonmetals; oxygen, sulfur & selenium. These elements usually gain or share two electrons when reacing with other elements
halogen family
Group 17 of the periodic table contains flourine, chlorine, bromine, iodine, and astatine
lanthanides and actinides
The elements at the bottom of the periodic table - fit in periods 6 & 7
group
Vertical column of elements in the periodic table
period
a horizontal row of elements in the periodic table
diatomic molecules
a molecule compound of two identical atoms
electron
a negatively charged particle
nuclear fusion
a nuclear reaction in which 2 nuclei combine to form more massive nuclei with the simultaneous release of energy
pure substance
a sample of matter, either a single element or a single compound, that has definite chemical and physical properties
plasma
a state of matter in which atoms are stripped of their electrons and the nuclei packed closely together
element
a substance that cannot be separated or broken down into simpler substances by chemical means
nonmetal
an element that conducts heat and electricity POORLY
metalloid
an element that has properties of both metals and nonmetals
metal
an element that is shiny and that conducts heat and electricity WELL
supernova
an enormous explosion of a giant star
isotope
atoms of the same element that have different numbers of neutrons
ductile
can be drawn into thin wires
malleable
can be hammered into thin sheets
nonmetals
elements that are usually dull in appearance, poor conductors of heat and electricity, gases at room temperature
carbon family
group 14 - gain lose or share 4 electrons
nitrogen family
group 15 - gain or share 3 electrons
alkaline earth metals
group 2 on the periodic table;very reactive metals
semiconductors
metalloids are called semiconductors, have properties of both metals and nonmetals; somewhat malleable and ductile
alloys
mixture of metals
neutron
neutral particle of an atom
synthetic elements
not found in nature, made in machines called accelerators, some of the elements with an atomic number higher than 92
noble gases
one of the elements of group 18 of the periodic table(helium, neon,argon, krypton, xenon, and radon); noble gases are unreactive
chemical symbol
one or two letters that represent an element's name
proton
positively charged particle of an atom
atomic mass
the average mass of all the isotopes of an element
nucleus
the center of an atom
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 metals
the highly reactive metallic elements located in group 1 of the periodic table
atomic number
the number of protons in the nucleus of an atom
