How do models help scientists predict the polarity of molecules? Explain in 2-3 sentences.

Models show the orientation of bonds in the molecule

Explanation:

Given a molecular model, a scientist will first identify the electro negativities of the atoms in individual bonds. This will give the scientist an idea whether there are polar bonds in the molecular model or not. Secondly, he checks the orientation of the bonds to decide if the entire molecule is expected to have an overall dipole moment.

Molecules may contain polar bonds and still do not possess an overall dipole moment due to the orientation of the bonds in space. Hence the usefulness of visualizing the molecule using a model.

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.

thats a little if u want the answer just look it up on google thats what i do haha : )