Magnesium has three isotopes: Magnesium-24 with a mass of 23.98504 amu and an abundance of 78.70%, magnesium-25 with a mass of 24.98584 amu and an abundance of 10.13%, and magnesium-26 with a mass of 25.98259 amu and an abundance of 11.17%.
Without doing the calculations, should the atomic mass of magnesium be closer to 25, 26, or 27 amu? Explain how you know.