I really need help! Co-60 is used medically for radiation therapy as implants and as an external source of radiation exposure. The half-life 0f Co-60 is 5, 272 years. How much of a 2.000 mg sample will remain after 21, 088 years? You must show your work to receive credit. Show calcs and don't forget sig fig processes.

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance

you need to have a picture of the atom that way we can answer it