help! help! plz which important property did mendelea use to classify his elements in the period table and did he stick to that ​

He used atomic weight as his basis and then arranged the known elements, the weight steadily increasing as it went on. He DID stick to the basis, leaving blank spaces for unknown elements. Hope this helps a lot!

Explanation:

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

they are made of gases.

they have a spherical shape.

they make energy through fusion.