The question is 22 I need help with

Which uses electromagnetic radiation to discover the properties and composition of bodies in space? space probe space station space shuttle space observatory

How can the periodic table be used to predict the behavior of elements?

Covalent bonds generally form when the bonded elements have a difference in electronegativity less than 1.5. subtract the electronegativities for the following pairs of elements and predict whether they form a covalent bond. electronegativity difference of c and c: ionic covalent electronegativity difference of mg and cl: ionic covalent