The % oxygen by mass of a Group 2 oxide is 39.7%. Name the Group 2 element.Group of answer choicesMgSrBaCaBe

To answer this question, we need to use the concept of mole ratios and the periodic table.

1. First, we need to know the molar mass of oxygen, which is 16 g/mol.

2. The question states that the % oxygen by mass in the compound is 39.7%. This means that the remaining 60.3% is the mass of the Group 2 element in the compound.

3. We can use the periodic table to find the molar masses of the Group 2 elements: Be (9.01 g/mol), Mg (24.3 g/mol), Ca (40.08 g/mol), Sr (87.62 g/mol), and Ba (137.33 g/mol).

4. We need to find a Group 2 element whose molar mass is approximately 60.3% of the total molar mass of the oxide.

5. If we calculate 60.3% of the molar mass of each of these oxides (which is the molar mass of the Group 2 element plus 16 g/mol for the oxygen), we find that calcium (Ca) is the closest, with a molar mass of 56.08 g/mol.

6. Therefore, the Group 2 element in the oxide is calcium (Ca).