An unknown compound was discovered to have the formula X2O3, where O stands for oxygen. What is the ion charge of the unknown element X?

Explanation:

The valency of element is 3 and formula of its chloride is XCL_3XCL

3

Explanation: The neutral oxide of the element X , X_2O_3X

2

O

3

is formed by the combination of X^{3+}X

3+

and O^{2-}O

2−

. Thus the valency of the element is X as it has lost three electrons to acquire stable noble gas configuration.

Similarly oxygen has gained two electrons to attain stable noble gas configuration and thus has a valency of two.

The chloride of the element X is formed by combination of X^{3+}X

3+

and Cl^{-}Cl

−

and thus to form a neutral compound XCl_3XCl

3

is formed.

petroleum? coal maybe?

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms