How is the number of neutrons in the nucleus of an atom calculated?
a. add the number of electrons and protons together.
b. subtract the number of electrons from the number of protons.
c. subtract the number of protons from the mass number.
d. add the mass number to the number of electrons.

The correct answer is Option c.

Explanation:

Neutrons are the subatomic particle which is present in the nucleus of an atom.

Mass number is defined as the sum of number of protons and number of neutrons that are present in an atom.

Mass number = Number of neutrons + Number of protons

Number of neutrons = Mass number - Number of protons

From the above information, the correct answer is Option c.

well in order to answer this question you have to provide more information < 3

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"