What does passionately moaning mean

Asingle atom of an element has 21 neutrons, 20 electrons, and 20 protons. which element is it? ok o z

1. combine iron and copper (ii) sulfate solution. (hint: iron will form the iron (iii) ion) fe + cuso4 → 2. combine lead (ii) nitrate and potassium iodide solutions. pb(no3)2+ kl → 3. combine magnesium metal and hydrochloric acid solution. mg + hcl → 4. electrolysis (splitting) of water. h2o → 5. burning magnesium. mg + o2 →

Needthe meter is the standard unit for: 1) height 2) length 3) weight 4) mass