Which of these equations is balanced? a. h2o+co > h2co3 b. 2nacl +h2so4 > na2so4 + 2hcl c. 2cao+ h2o > ca(oh)2 d. mn +fe > mns + fe

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.