Why does one atom have a partial negative charge in a polar covalent bond?

that atom has a greater attraction for electrons.

that atom has a lesser attraction for electrons.

that atom is more likely to form ionic bonds.

That atom has a greater attraction for electrons.

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me