21 terms

Science 9 Chapter 2

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chemical symbol
one or two letters given to a single element
metal
typically hard, shiny, malleable, ductile and good conductors of heat and electricity
non-metal
tend not to have the same properties as metals and are usually gases or brittle solids at room temperature
periodic table
a chart that organizes the elements according to their physical and chemical properties, gives each element's name, symbol, atomic number, atomic mass, and ion charge
atomic number
number of protons in the nucleus of each atom of an element, is always a whole number
atomic mass
an average atom of an element, always written as a decimal number
ion charge
an electric charge that forms on an atom when it gains or loses electrons
ion
an electrically charged atom
negative ion
an atom that has gained an electron, are elements on the right side of the table
positive ion
an atom that has lost an electron, are elements on the left side of the table
multiple ion
atoms that can form ions in more than one way
metalloids
elements that share some properties with metals and some properties with non-metals solids, can be shiny or dull, may conduct electricity, poor conductors of heat, brittle and not ductile.
metals
One of a class of elements that are good conductors of heat and electric current; metals tend to be ductile, malleable, and shiny
non-metals
elements on the periodic table that are usually dull in appearance, poor conductors of heat and electricity, gases at room temperature, brittle and not ductile
periods
each horizontal row in the periodic table
family
chemical families or groups are arranged in vertical column in the periodic table
alkali metals
metallic elements in group 1 of the periodic table which are highly reactive, have a low melting point, good electrical conductivity, and they are soft and shiny when first cut
alkaline earth metals
metallic elements in group 2 of the periodic table which are harder than the alkali metals and are also less reactive
halogens
group 17; contains nonmetals; 7 electrons in its outermost energy level; very reactive; poor conductors of electric current; never in its uncombined form in nature; combine with most metals to form salts
noble gases
one of the elements of group 18 of the periodic table(helium, neon,argon, krypton, xenon, and radon); noble gases are unreactive
Bohr Model Diagrams
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