The element X and Y

So, let’s say there are 2 elements, X and Y. X does not have a fix shape. X expands and contract rather fast. Under good care, it can be melted easily. X has a strong reaction with element gold, silver and diamond. X is very attracted to Y. X is often regarded as very expensive and useful aesthetical wise. The maintenance cost of X is very high. Being a very explosive element, inexperience individuals are not encouraged to own any of element X and for those who do, always handle with care.

Y also doesn’t have a shape. Y often changes shapes and melt according to element X. General chemical tests suggest that Y has very strong reaction with ethanol contents and nicotine. Without presence of X, Y is often regard as nothing but useless. As of now, there are only a handful of good products out of element Y. There are, however, high concentration of substandard product of Y.

So what's X and Y? Chem Students? Com'on!! ;)

Source of picture: http://www.corrosionsource.com/handbook/periodic/periodic_table.gif