[...]... protons and the number of neutrons for each example sum to the mass number that is given In part (a), for example, there are 17 protons and 18 neutrons, which sum to give a mass number of 35 , the value given in the problem In part (b), 17 protons + 20 neutrons = 37 In part (c), 19 protons + 22 neutrons = 41 In part (d), 6 protons + 8 neutrons = 14 protons Recall that the 14 in carbon-14 is the mass... century, the periodic table was deemed "the most predictive tool in all of science." We will take a more detailed look at this keystone of chemistry in Chapter 7 The following Bringing Chemistry to Life box describes the distribution of the elements in Earth's crust Bringing Chemistry to Life Distribution of Elements on Earth Earth's crust extends from the surface to a depth of about 40 krn (about 25 1ni)... right of the table The two rows of metals beneath the main body of the table are set apart to keep the table from being too wide Actually, lanthanum (57) should follow barium (56), and actinium (89) should follow radium (88) The 1-1 8 group designation has been recommended by the International Union of Pure and Applied Chemistry (IUPAC) but is not yet in wide use In this text, we generally use the standard... prefixes, where appropriate, to indicate the number of atoms of each element In part (a) the molecule contains one nitrogen atom and three fluorine atoms We will omit the prefix mono- for nitrogen because it is the first element listed in the formula, and we will use the prefix tri- to denote the number of fluorine atoms In part (b) the molecule contains two nitrogen atoms and four oxygen atoms, so we... guidelines Setup In part (a) there is no prefix for sulfur, so there is only one sulfur atom in a molecule of Think About It Double-check that the subscripts in the formulas match the prefixes in the compound names: (a) 4 = tetra and (b) 4 = tetra and 10 = deca the compound Therefore, we will use no prefix for the S in the formula The prefix tetra- means that there are four fluorine atoms In part (b) the... possible whole numbers (without altering the relative numbers of atoms) Setup The molecular formulas in parts (a) and (b) each contain subscripts that are divisible by common numbers Therefore, we will be able to express the formulas with smaller whole numbers than those in the molecular formulas In part (c), the molecule has only one 0 atom, so it is impossible to simplify this formula further Think... are the smallest possible whole numbers In part (a), for example, the ratio of C:H:O in the molecular formula is 6: 12:6, which is equal to 1:2: 1, the ratio expressed in the empirical formula Solution (a) Dividing each of the subscripts in the molecular formula for glucose by 6, we obtain the empirical formula, CH2 0 If we had divided the subscripts by 2 or 3, we would have obtained the formulas C3H... facilitating communication among scientists and providing a useful way of labeling an overwhelming variety of substances Mastering these lUles now will benefit you tremendously as you progress through your chemistry course You must be able to name a compound, given its chemical fonnula, and you must be able to write the chemical fonnula of a compound, given its name of chemical nomenclature, ' ... discover that neon has a third stable isotope (neon-21) with natural abundance 0.27 percent (Figure 2.11) This example illustrates how very important experimental accuracy is to a quantitative science like chemistry Early experiments failed to detect neon-21 because its natural abundance was so small Only 27 in 10,000 Ne atoms are neon-21 Detecting screen Accelerating plate:sr::;,:;;Electron beam ~+ Magnet... CI, (c) 41K, and (d) carbon-14 NCl, Strategy Recall that the superscript denotes the mass number, (A) , and the subscript denotes the atomic number, (Z) In the case where no subscript 'is shown, as in parts (c) and (d), the atomic number can be deduced from the elemental symbol or name For the purpose of determining the number of electrons, remember that atoms are neutral, so the number of electrons