A metal oxide has the formula X₂O, where X is a Group 1 metal - OCR Gateway - GCSE Chemistry Combined Science - Question 2 - 2023 - Paper 9

To find the relative atomic mass of X, we can use the formula for the relative formula mass:

$ext{Relative formula mass} = (2 imes Aᵣ(X)) + Aᵣ(O)$

Substituting in the known values gives:

$94.2 = (2 imes Aᵣ(X)) + 16.0$

Rearranging gives:

$2 imes Aᵣ(X) = 94.2 - 16.0 = 78.2$

Thus,

$Aᵣ(X) = \frac{78.2}{2} = 39.1$

The relative atomic mass of X is 39.1. Looking at the options, Potassium (K) has an atomic mass of approximately 39.1. Therefore, the name of X is Potassium.

B Potassium