pure subsatnces that can't be broke down futher into different chemical constituents. 89 which occur in nature. hydrogen, oxygen, and carbon make up 98 percent of most animal and plant bodies.
small particals that are that are in an element
are combinations of two or more atoms
all atoms are made of
protons neutrons and electrons
particals positively charged
are much smaller (have less mass) and are negative electrical charge
particals with no charge
is in the atom center which contains protons and neutrons and the electrons orbit at a great distance
are electrons at a specific diastance that gives them higher energy levels the futher they travel away from the nucleus.
are atoms with the same number of protons but different numbers of neutrons. carbon dateing is based this
length of time required for half of the radioactive atoms in a sample to decay
electron numbers vary so the whole atom has a specific positive or negative charge. this means that the atom does not have the same amount of electrons and protons.