study study ch 2 & 3

matter
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Terms in this set (15)
matter
is anything that takes up space and has mass
element
pure substance made from matter
elements combine to form
compounds
atom
Smallest particle of an element
atomic structure
protons (+) neutrons = neutral, electrons (-)
atomic number
# of protons
mass #
sum of protons and neutrons
isotopes
different forms of an element distinguished from one another by # of neurons
C12= 6 protons and 6 neurons
mass #= 12
radioactive isotopes
nucleus readily decays, giving off subatomic particles and electromagnetic energy
electron shell
has one to five electron shells
holds 8 electrons
except first shell only holds 2
valence shellatoms outermost electron shell valence shell full its stable if not full tends to react with other atoms in ways to make shell fulloutlet ruleatoms most stable when 8 electrons are in valence shell -atoms will share, gain or give up electrons to get to 8 -2 hydrogen share one electron with oxygen forming a covalent bond resulting in h20 or waterionatom that has an electrical charge either negative or positiveionic bondschemical bonding involves electrostatic attraction between oppositely charged ionscovalent bondsshare electrons in mutually stabilizing relationship electrons move back and forth stronger than ionic