What is the mass of the most abundant isotope?
a. mass number is the mass of the most abundant isotope
b. mass number is the mass of the protons in the nucleus
c. mass number is the number of protons in the nucleus
d. mass number is the atomic mass of a particular isotope

The answer to your question is : A. mass number is the mass of the most abundant isotope

Explanation:

A. mass number is the mass of the most abundant isotope  This is the right answer because we need to consider the mass of the most abundant isotope.

B. mass number is the mass of the protons in the nucleus . To calculate the mass number we need to consider not only the protons but also the neutrons, this option is wrong.

C. mass number is the number of protons in the nucleus . This option is incomplete, because we need to sum the protons and neutrons to get the mass number.

D. mass number is the atomic mass of a particular isotope. Mass number is not only of a particular isotope, we need to consider the most abundant isotope, so this answer is wrong.

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