Prescription painkillers, also known as opioid pain relievers, include oxycodone, hydrocodone, hydromorphone, and others. Many people who abuse these painkillers become dependent. Some even move on to abusing illegal narcotics, such as heroin.
The first 92 (through uranium) occur naturally. The others are transuranics.. As of 2009, there are 118 ending with ununoctium. All together there are 117 elements on the periodic table, 94 of which occur naturally on earth. According to Wikipedia, there are 117 elements that have been isolated or synthesized, with a gap between element 116 and element 118.
A simple Google search would have sufficed. Number of elements in most of the periodic tables is 118 due to the perfect symmetry. However,the last properly named element is Copernicum which has atomic number of 112. The rest of the elements are just tentatively named. They will be properly named once there existence is properly proved.