When hydrogen is attached to a more electronegative element?

When hydrogen is attached to a more electronegative element, the electronegative atom becomes partially negative and the hydrogen atom becomes partially positive

Explanation:

Electronegativity is the tendency of an atom to draw electrons closer to itself when it is bound to another different chemical element through a covalent bond, that is, where electrons share, considering that molecule as isolated.

Because of electronegativity when a hydrogen atom is covalently bonded to a more electronegative atom, the hydrogen electron is strongly attracted to the other atom, leaving hydrogen partially positive.

Take for example an HCl molecule. The chlorine atom attracts electrons with greater intensity than hydrogen. Therefore, we say that chlorine is more electronegative than hydrogen. This forms an electric dipole (μ), which are two electric monopoles, with electrons tending to be more attracted to chlorine. Then the H ─ Cℓ bond will have a negative partial charge on chlorine (δ-) and a positive partial charge on hydrogen (δ +). So this is a molecule with electronegativity difference and is polar.

the atomic mass is the bottom number on the element.

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