Which of the following are always different for isotopes of the same element?

a. Total number of charged particles
b. Atomic number
c. Number of electrons
d. Mass number
e. Number of protons

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.