Question

$14$ g of element X combines with $16$ g of oxygen. On the basis of this information, which of the following is a correct statement?

• A. The element X could have an atomic weight of $7$ amu and its oxide is $XO$
• B. The element X could have an atomic weight of $14$ amu and its oxide is $X_{2}O$
• C. The element X could have an atomic weight of $7$ amu and its oxide is $X_{2}O$
• D. The element X could have an atomic weight of $14$ amu and its oxide is $X{O}_2$

Answer 1

The correct option is C The element X could have an atomic weight of $7$ amu and its oxide is $X_{2}O$

$14$ g of an element X combines with $16$ g of oxygen, then the element X could have an atomic weight of $7$ amu and its oxide is $X_{2}O$.
When the atomic weight is $7$, $14$ g will corresponds to $2$ moles.
$16$ g of oxygen corresponds to $1$ mole.

The formula $X_{2}O$ suggests the valency of $1$ for X.