How close a measured value is to the value is to the accepted value

You could use percent error. Absolute | | of accepted value minus experimental value \ divided by accepted value multiply by 100 and that is your answer

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom