How many valence electrons do halogens have?

The peak wavelength for the blackbody curve of a star is in the uv range. assuming the radiation from this star can reach earth, would you be able to see it?

What is the area in square meters of 448 g ai foil that has a thickness of 23921 nm? the density is 2.70 g/cm

#7 how does the structure of amino acids allow them to form a polypeptide? each amino acid has an amino group and a carboxyl group. each amino acid has a hydrogen atom and a carboxyl group. each amino acid has a carboxyl group and an r group. each amino acid has an r group and a hydrogen atom.