Giselle is pairing ions to create stable binary ionic compounds. she knows that the sum of charges of the two ions must be zero in order for the compound to be stable. which ion could be paired with a potassium ion, k +, to form a stable binary compound?

In a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. what should be the radius of curvature of the cornea such that the image of an object 40.0 cm from the cornea’s vertex is focused on the retina?