Which combination makes up most of the mass of an atom? A. Electron and proton
B. Electron and neutron
C. Proton and neutron
D. None of these make up atom’s mass

Insoluble sulfide compounds are generally black in color. which of the following combinations could yield a black precipitate? check all that apply. na2s(aq)+kcl(aq) li2s(aq)+pb(no3)2(aq) pb(clo3)2(aq)+nano3(aq) agno3(aq)+kcl(aq) k2s(aq)+sn(no3)4(aq)