Answer:
Of the 118 elements that have been discovered, there are 90 elements that occur in nature in appreciable amounts.
Explanation:
Depending who you ask, there are another 4 or 8 elements that occur in nature as a result of radioactive decay of heavier elements. So, the grand total of natural elements is 94 or 98. As new decay schemes are discovered, it's likely the number of natural elements will grow. However, these elements will likely be present in trace amounts.
There are 80 elements that have at least one stable isotope. The other 38 elements exist only as radioactive isotopes. Several of the radioisotopes instantly decay into a different element.
It used to be believed that of the first 92 elements on the periodic table (1 is hydrogen and 92 is uranium) that 90 elements occur naturally. Technetium (atomic number 43) and promethium (atomic number 61) were synthesized by man before they were identified in nature.
