They are found in all three states of existence. Here are some other physical properties of halogens that make them a very unique family of elements. Appearance Appearance wise fluorine exists as a pale yellow gas that is poisonous in nature, while chlorine is similarly poisonous but exists as a pale green colored gas.alogens range from solid (I2) to liquid (Br2) to gaseous (F2 and Cl2) at room temperature. The chemical properties are more uniform. The halogens have very high electronegativities. Fluorine has the highest electronegativity of all elements.
An example of a phenotypic trait is hair color; there are underlying genes that control the hair color, which make up the genotype, but the actual hair color, the part we see, is the phenotype.
Some hair is dark, some is white and some hair is completely white or gray. Hair color is dependent on the pigment in the cortex that forms the main horny portion of the hair. Gray or white is simply hair without pigment. This same chemical pigment is what determines our skin color.