To determine whether people have worked enough to meet the requirements, the SSA requires people to earn a certain number of work credits. Work credits are essentially income that is assigned a value. In general, you must have accumulated 40 work credits (20 in the past 10 years) to be eligible for disability.
Bromine is a chemical element with symbol Br and atomic number 35. It is the third-lightest halogen, and is a fuming red-brown liquid at room temperature that evaporates readily to form a similarly coloured gas. Its properties are thus intermediate between those of chlorine and iodine.
In chemistry and physics, the atomic number of a chemical element (also known as its proton number) is the number of protons found in the nucleus of an atom of that element, and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element.