What field of study did bohr inspire

Iron is a transition metal with multiple oxidation numbers. (answer the following) a. what is the iron (ii) ion? how does it differ from the iron (iii) ion? b. if iron were to bond with oxygen, predict the formula for each oxidation number of iron. c. how would each formula be named?

Matter that emits no light at any wavelength is called

According to the image below, which season is about to begin in the southern hemisphere? a. summer b. autumn c. winter d. spring