Kathleen is testing a mixture containing a certain substance. She takes a sample from the top and the bottom. The sample from the bottom has more of the substance than the sample from the top. What is this mixture? A) a solution
B) heterogeneous
C) homogenous

Astable electron arrangement for an atom is one that does not easily change. how is this arrangement arrived at? a. valence electrons are transferred or shared to create a full outer shell of electrons. b. valence electrons are discarded into space to create a full outer shell of electrons. c. protons (positive charge) pair with valence electrons (negative charge) to create a strong bond. d. outer shells with valence electrons are transferred or shared.