half life
Time it takes for half of an isotope to decay
isotopes
Atoms of the same element having different masses because they contain different numbers of neutrons.
20
Initially, there are how many parent atoms? (Write answer as a number)
radioactive decay
A spontaneous process in which unstable nuclei lose energy by emitting radiation
parent element
The original element before it turns into another element through decay.
daughter element
the new element that results from the radioactive decay of the parent element
protons
Positively charged particles
neutron
A small particle in the nucleus of the atom, with no electrical charge
electron
A subatomic particle that has a negative charge
element
A pure substance made of only one kind of atom
15
The halflife of Na-25 is how many hours?
47 days
How long is the half-life of mercury-203?
75
Approximately what percentage of daughter material is there in ninety-four days?
5700
Approximately what is the half-life of carbon 14?
30 minutes
If 20.0 g of a radioactive isotope are present at 1:00 PM and 5.0 g remain at 2:00 PM, what is the half life of the isotope?