I don’t get the question. is there a worksheet?
Number of neutrons = mass number - atomic number = 40 - 19 = 21 answer
Answer:
They are called insulators
Answer:
Phenolphthalein is an acid indicator, which means when we add water (pH 7) to it, it ionizes giving a pink color. We all know acid gives in solution. When we add phenolphthalein to acid due to the common ion effect concentration increases. turned the solution pink.
Explanation: