In a compound having molecular formula XY, element 'X' belongs to the 3^rd period and the 2^nd group, whereas, element 'Y' belongs to the 2^nd period and the 16^th group. What is the relative molecular mass of the compound XY?

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Answer 1

The correct answer is 40u.

Key Points

Element 'X' belongs to the 3rd period and the 2nd group of the periodic table, which identifies it as Magnesium (Mg) with an atomic mass of 24u.
Element 'Y' belongs to the 2nd period and the 16th group of the periodic table, which identifies it as Oxygen (O) with an atomic mass of 16u.
The molecular formula XY indicates a 1:1 ratio of Magnesium to Oxygen in the compound.
The relative molecular mass is calculated as the sum of the atomic masses of X and Y: 24u (Mg) + 16u (O) = 40u.

Additional Information

Periodic Table:
- The periodic table is a tabular arrangement of chemical elements, organized by their atomic number, electron configuration, and recurring chemical properties.
- Elements are arranged in rows called periods and columns called groups.
Magnesium (Mg):
- Magnesium is a chemical element with the symbol Mg and atomic number 12.
- It is a shiny gray solid, often used in alloys and as a reducing agent in the production of metals.
Oxygen (O):
- Oxygen is a chemical element with the symbol O and atomic number 8.
- It is a highly reactive nonmetal and an oxidizing agent that readily forms oxides with most elements and compounds.
Relative Molecular Mass:
- The relative molecular mass (molecular weight) of a molecule is the sum of the atomic masses of all the atoms in the molecule.
- It is calculated using the atomic masses of the constituent elements as given in the periodic table.