<span>P<span>F5
</span></span><span> has a zero dipole moment as it doesn't have a lone pair of electrons. the geometry is trigonal bipyramidal. The axial P-F bonds "cancel" each other. The equatorial P-F bonds are oriented as trigonal planar, so those three (like in BF3) "cancel" as well.
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Dipole moment of a compound is different from the dipole moment of a bond. You need to look at ALL bonds for the overall dipole moment of a molecule.
Low friction between you/the ski vs the snow.
if you think about it its kinda like you and a slip and slide...water helps decrease friction so you slide (snow does the same for the skiing) but without it you just flop and don't go anywhere (very easily anyway).
The Lewis dot structure of Mg²⁺ is shown in the picture attached.
In Mg atom, the outermost orbit has 2 electrons.
The atom has the ability to lose its 2 electrons to become Mg²⁺
The Mg²⁺ ion have completed its vacancy in the second orbit having 8 electrons.
Therefore, the valency of Mg becomes 2+ as it loses its electron.
PV = constant
V doubles, P will become half
New pressure = 100/2 = 50 torr