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.
There are about 118 elements given in the periodic table according to their atomic number. An element is a chemical substance which consists of only a single type of atoms, hence they are pure. For example, the smallest element is the hydrogen, and silver, gold, platinum are some of the commonly known precious elements. Each element has an atomic mass, atomic number, symbol, electronic configuration, etc.