7. Tellurium consists of 3 common isotopes. Half of tellurium atoms have a mass of 127. and another 0.45 of tellurium atoms weigh 128. What is the mass of the remaining isotope? The atomic mass of tellurium is 127.5

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

it's filtration, but this is an assumption so my apologies if i got this