The number of possible elements is not known. A very early suggestion made by Elliot Adams in 1911, and based on the arrangement of elements in each horizontal periodic table row, was that elements of atomic weight greater than 256Â± (which would equate to between elements 99 and 100 in modern-day terms) did not exist.
IRS debts can only legally be collected for 10 years, but there are many events that may stop that 10 year clock from running. This is known as tolling the statute of limitations. Events that stop or toll the statute of limitations from running include:
The IRS only requires 3 years of tax records if you are audited. But if they find you are under-reporting your income (i.e. you owe taxes) they can request up to 7 years of tax records. However, where the IRS suspects fraudulent or missing returns, there is no limit on how far they can go back.