If copper loses 2 electrons write the symbol for its ion

1) according to the law of conservation of mass ,in all chemical reactions total mass is unchanged

According to arrhenius theory of acid and bases, an acid is a proton donor, while base donates hydroxyl ions. further, acid and base reacts to form salt and water.consider following example.hcl    +      h2o          →      cl-          +      h3o+here, hcl has donated a proton, hence it is an acid.now consider following reactionhcl      +      naoh            ↔      nacl      +        h2oin this reaction, hcl donates proton, hence it is acid. on other hand, naoh donates hydroxyl ion (i.e. hence it is a base.   

Neptunium is the only of those 4 that doesn’t occur naturally.