The first periodic table was organized by atomic number
atomic mass
chemical name
chemical symbol

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?

Which of these metals are magnetic?

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?