Question

what causes the partial positive charge on the hydrogen atom in a water molecule? the hydrogen atom loses electrons to the oxygen atom. the hydrogen atom gains electrons from the oxygen atom. the hydrogen atom shares electrons unequally with the oxygen atom. the hydrogen atom shares electrons equally with the oxygen atom.

Explanation:

In a water molecule (\(H_2O\)), oxygen is more electronegative than hydrogen. Electronegativity is the ability of an atom to attract electrons in a chemical bond. Since oxygen is more electronegative, it attracts the shared electrons in the \(O - H\) bonds more strongly than hydrogen does. This unequal sharing of electrons (a polar covalent bond) results in the hydrogen atom having a partial positive charge (\(\delta+\)) and the oxygen atom having a partial negative charge (\(\delta-\)).

• The first option ("The hydrogen atom loses electrons to the oxygen atom") is incorrect because in \(H_2O\), it is a covalent bond (electrons are shared, not transferred as in an ionic bond).
• The second option ("The hydrogen atom gains electrons from the oxygen atom") is incorrect because oxygen, being more electronegative, has a greater pull on the shared electrons, not the other way around for hydrogen gaining electrons in the sense of having a net gain (it's about unequal sharing).
• The fourth option ("The hydrogen atom shares electrons equally with the oxygen atom") is incorrect because of the difference in electronegativity between \(O\) and \(H\) (electronegativity of \(O = 3.44\), electronegativity of \(H= 2.20\)), so the sharing is unequal.

Answer:

The hydrogen atom shares electrons unequally with the oxygen atom.