Your answer should be C.) +2. "All the elements in Group 2 have two electrons in their valence shells, giving them an oxidation state of +2."
Credits: https://chem.libretexts.org/Core/Inorganic_Chemistry/Descriptive_Chemistry/Elements_Organized_by_Blo...
Hopefully this has helped! :)
Most metamorphic processes take place a few kilometers below Earth's surface. Metamorphic processes result due to intense heat and high pressure below the Earth's surface. Also, metamorphism can occur on two scales, contact and regional.
This problem is honestly, very easy. Just grab a periodic table and find the element in Group 1 and Period 7. But first, let's discuss how the elements are arranged systematically in a periodic table. There are a lot of scientists who contributed to it, but the most famous one is Dimitri Mendeleev. He arranged the elements according to their atomic number. The elements starts from 1 which is Hydrogen up to the heaviest known elements which is Oganesson with an atomic number of 118. As you can observe, there is a gap between groups 3 and 4. This is done so that the periodic table does not take too much space horizontally. Thus, they are just placed at the bottom. These elements are called lanthanides (upper row) and actinides (lower row). The rows in the periodic table are called groups, and the columns are called periods.
Now, the element at the lower left corner (Group 1, Period 7) is Francium, abbreviated as Fr. It has an atomic number of 87. Some elements are actually synthesized, but Francium is a naturally occurring radioactive element. It was discovered by Marguerite Perey in France.
1. For the first question, we must find the mass of the anhydrous salt, MgSO₄. The molar mass for MgSO₄·7H₂O is 246.47 g/mol, while that of MgSO₄ is 120.37 g/mol.
7.834 g MgSO₄·7H₂O * 1 mol MgSO₄·7H₂O/246.47 g * 1 mol MgSO₄/1 mol MgSO₄·7H₂O * 20.37 g MgSO₄/mol = <em>0.647 g MgSO₄</em>
2. Mass of Water = Mass of sample - Mass of anhydrous sale
Mass of water = 7.834 - 0.647 = 7.19 g
Percent Water in Hydrate = 7.19/7.834 * 100 = <em>91.74%</em>