Chemical element of metals. Cu comes from Cuprum, Fe comes from Ferrum, Ag from Argentum. The symbols were not followed by a period (full stop) as with abbreviations. Later chemical elements were also assigned unique chemical symbols, based on the name of the element, but not necessarily in English. For example, sodium has the chemical symbol 'Na' after the Latin "natrium". The same applies to "W" (wolfram) for tungsten, "Fe" (ferrum) for iron, "Hg" (hydrargyrum) for mercury, "Sn" (stannum) for tin, "K" (kalium) for potassium, "Au" (aurum) for gold, "Ag" (argentum) for silver, "Pb" (plumbum) for lead, "Cu" (cuprum) for copper, and
Au pair pair wages exceed the applicable dollar threshold, then the host family must withhold social security and Medicare taxes and report them on Schedule H of Form 1040 and on Form W-2. The host family must apply for an Employer Identification Number (EIN) if it is required to withhold tax and file Form W-2. Potential au pairs must: Au pairs in the United States are categorized by program types. Most au pair organizations in the United States classify au pairs by the following programs: Standard Au Pair Program The Standard Au Pair program is the most popular program available. Standard au