Can someone Please help me?

How many neutrons does an element have if its atomic number is 50 and its mass number is 166

Which type of intermolecular force is pbr3

Which statement is true about the model of the electromagnetic spectrum a: it change the frequencies of light. b: it compare wavelengths of light. c: the color of light waves can be changed using the model. d: the intensities of light waves can be decreased using the model.