Answer: It is important to wet the filter paper in the Buchner funnel first with cold re crystallization solvent before the re crystallization mixture being filtered to minimize gaps around the edges of the filter paper which can prevent mechanical impurities from passing through. This gives better filtration where most impurities can be filtered. Furthermore, it provides good vacuum.
An atom. An atom has no charge. The number (and charge) of protons in atom's nucleus is balanced by the electrons orbiting the nucleus. If it had charge it would be called an ion.
