What is the difference between mass number and atomic number?

Zoe is investigating the composition of substance a, an unknown substance. using chemical processes, she analyzes substance a and determines it is composed of sodium, oxygen, and hydrogen atoms in a ratio of 1 : 1 : 1. what is substance a? a. a compound b. an element c. a heterogeneous mixture d. a homogeneous mixture

What is the polyatamic ion of borate

This image is an example of a(n) a) atom. b) compound. c) mixture. d) molecule.