Answer:
the protons
Explanation:
the number of protons is constant for each sample of the element. If the number of protons differs, then it is a different element.
Answer is Sodium Hydroxide.
When the concentration is expressed in percentage, you simply have to divide the amount of substance to the total amount of the mixture, then multiply it by 100. In this case, when you want to find the percentage of P in the sample, the solution is as follows:
%P = 7.5 g/100 g * 100 =<em> 7.5%</em>