Question

Which of the following statements about the periodic table's organization is true? (Select all that apply.)
It is organized by reactivity.
It is organized by families.
It is organized by atomic number.
It is organized by atomic mass.
It is organized by periods and groups.

Answer 1

I don't know if it is organized by reactivity
it is organized by families
it is organized by atomic number
it is NOT organized by atomic mass
it is organized by periods and groups

Answer 2

It is organized by atomic mass
It is organized by periods and groups