chemical level organization
Terms
undefined, object
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- chemical elements
-
substance that cannot be
split in simpler substance - how many elements
-
112 element 92 occur
naturally - chemical symbol
-
1 or 2 letters in
english, latin, or
another language - H, C,O,N,Ca,Na
-
hydrogen, carbon, oxygen,
nitrogen, calcium, sodium - elements in body
- 26
- 96% of elements
-
oxygen, carbon,
hydrogen, nitrogen -
8 other elements present
in body -
calcium, phosphorus, potassium,
sulfur, sodium, chlorine,
magnesium, iron -
how many additional
elements -
14 trace elements
.2% - atoms
-
smallest units
of matter that
retain properties
of element - subatomic particles
-
protons, neutrons,
electrons - nucleus
-
dense central
core of atom - electron shells
-
electron moving
about central
core - 1st 2nd 3rd + shells
- 2, 8, 18, 18
-
most massive
element - iodine
- electrons equal
- protons
- atomic #
- # of protons
- mass #
-
sum of protons
and neutrons - isotopes
-
different # of
neutrons - radioactive isotopes
-
unstable nuclei
decay(change) into
stable - half-life
-
time required for half
of radioactive atoms to
decay into stable form