An atom of a certain element has 19 protons, 19 electrons, and a mass number of 39. This element is very reactive. How many neutrons are in this atom? Record your answer and fill in the bubbles on your answer document. Be sure to use the correct place value.

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.