As a group, halogens exhibit highly variable physical properties. Halogens 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.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.
A gene can exist in many different forms, calledalleles. For example, letâs say that there is one gene which determines the color of your hair. That one gene may have many forms, or alleles: black hair, brown hair, auburn hair, red hair, blond hair, etc. You inherit one allele for each gene from your mother and one from your father. Each of the two alleles you inherit for a gene each may be strong (dominant) or weak (recessive).
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.