Which of the following best explains the forces acting upon polar molecules? answer !

D; They have partial charges and are bound together by dipole-dipole intermolecular forces.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

it takes on an electronical energy