A cation-exchange column is a type of chromatography that separates substances according to their charges. The cation-exchange column in particular has a negatively charged resin that will attract positively charged ions.
Applying this principle with amino acids, we can say, for example that the negatively charged ones (e.g., aspartate and glutamate) will elute first compared to the positively charged ones (e.g., lysine, arginine, and histidine), which will elute last.
I would be difficult to remove an electron from a Noble or Inert Gas (also known as the group 8 or 0 elements). This is because they all have filled outermost shells and as such the outermost shell would be held tightly to the nucleus and as such make it difficult to remove. Examples Helium, Neon, Argon, Xenon, Krypton and Radon
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Answer:
The answer is A. Polar covalent; negatively
Explanation:
Hydrogen bonds form between molecules containing polar covalent bond the hydrogen bond is been a hydrogen atom of one molecule and a partially negative charged atom of another.
Example 
(water):- It contain a slight positive charge on one side and a slight negative charge on the other.
