In a chemical reaction, only the atoms present in the reactants can end up in the products. No new atoms are created, and no atoms are destroyed. In a chemical reaction, reactants contact each other, bonds between atoms in the reactants are broken, and atoms rearrange and form new bonds to make the products.

Will give imagine you are given a mystery element. it is, however, a discovered and known element. you may perform a maximum of two observations or tests to determine its identity. time and money is critical, so you need to prioritize your tests. if you can get by with a single test, you get 100 super-geek points from your research lab team. pick your two tests, number them as #1 and #2, and justify why you think these two will certainly be enough (and why the first might well be enough all by itself.) the available tests are classification into metal, non-metal, or metalloid, count of valence electrons, count of electron shells, atomic radius (error range: +/- 1 pm), electronegativity (error range: +/- 0.1), first ionization energy (error range: +/- 10 kj/mole), melting point (error range: +/- 10 c), and boiling point (error range: +/- 20 c).