Which of these particles is the smallest? A. a proton

B. a nucleus

C. an electron

D. an atom

C

Explanation:

so basically, we can eliminate some answer choices right away.

an atom (answer choice D) is made up of all the other answer choices, so that is the largest (not the answer).

a nucleus (answer choice B) is made up of protons (answer choice A) and neutrons which means it is not the smallest either (not the answer).

now, we are left with a proton and an electron. electrons are much smaller than protons, so they are usually not included in an element's atomic mass. therefore, an electron is the smallest out of these answer choices.

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

lol for the pointsss