Calculate the average atomic mass of silver if 13 out of 25 atoms are silver -107 and 12 out of 25 atoms are silver -109

Endeleev saw trends in the physical and chemical properties of elements when he organized them by

How air particles exert a pressure on the inside of the balloon

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