Which part of the atom cannot have its location accurately determined and is modeled by a cloud around the center of the atom?

How many neutrons does a atom of cobalt have?

How many moles of oxygen gas are produced from the decomposition of six moles of potassium chlorate

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?