Here is the answer for the three of them
<span>N20 = 16 e-
</span><span>SeCl2 =20
</span><span>PBr3 = 26
Remember that t</span><span>o find the valence electrons in an atom you need to identify what group the element is in. An element in group 1A has 1 valence electron. If the element is in group 2A, then it has two valence electrons.</span>
Attraction between polar molecules
Larger molecules experience larger dispersion forces due to more distance of valance of electrons from the nucleus.
<h2>Cause of stronger dispersion force</h2>
Larger and heavier atoms and molecules have stronger dispersion forces than smaller and lighter ones because in a larger atom or molecule, the valence electrons are farther from the nuclei than in a smaller atom or molecule.
They are less tightly held to the nuclear charge present in the nucleus and can easily form temporary dipoles so we can conclude that larger molecules experience larger dispersion forces due to more distance of valance of electrons from the nucleus.
Learn more about London dispersion force here: brainly.com/question/1454795
Learn more: brainly.com/question/26139894
Energy
It travels in the form of energy waves
