A person throws 10 darts at the bull’s eye. None of them hit the bull’s eye, but they all hit in the outer most circle, near the number 19 A) accurate
B) precise
C)Both
D)Neither

Different isotopes indicate that an element will have different numbers of

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.

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