Question

The periodic table ____.

a. is arranged by atomic mass
b. was developed by early alchemists
c. is arranged by the number of protons
d. is divided into vertical periods and horizontal groups

It's either a or c I'm pretty sure but i don't know which one​

Answer 1

A. is arranged by atomic mass and/or number

Step-by-step explanation:

hope i helped

Answer 2

both a and c

Step-by-step explanation:

it shows the mass of the element along with protons