Chapter 2 - Atoms, Molecules, and Ions - Questions and Exercises - Exercises - Page 83: 2.40

(a) $^{51}_{23}$V$^{3+}$ (b) $^{127}_{53}$I$^{-}$ (c) $^{102}_{44}$Ru$^{3+}$ (d) $^{31}_{15}$P

(a) The element with 23 protons in the nucleus, which means the atomic number is 23, is vanadium, chemical symbol V. The superscript to the left of the chemical symbol would be the mass number, which is the total number of protons and neutrons in the nucleus of that atom. We add the number of protons, 23, to the number of neutrons, 28, to get a mass number of 51. The left subscript is the atomic number, which is 23. The superscript to the right of the chemical symbol is the charge of the ion. We figure this out by adding up the negative and positive charges to get a net charge. There are 23 protons, each with a single positive charge for a total charge of +23. The number of electrons is 20, each with a single negative charge for a total charge of -20. We add +23 to -20 to get a net charge of +3. The symbol for this ion would be $^{51}_{23}$V$^{3+}$. (b) The element with 53 protons in the nucleus, which means the atomic number is 53, is iodine, chemical symbol l. The superscript to the left of the chemical symbol would be the mass number, which is the total number of protons and neutrons in the nucleus of that atom. We add the number of protons, 53, to the number of neutrons, 74, to get a mass number of 127. The left subscript is the atomic number, which is 53. The superscript to the right of the chemical symbol is the charge of the ion. We figure this out by adding up the negative and positive charges to get a net charge. There are 53 protons, each with a single positive charge for a total charge of +53. The number of electrons is 54, each with a single negative charge for a total charge of -54. We add +53 to -54 to get a net charge of -1. The symbol for this ion would be $^{127}_{53}$I$^{-}$. (c) The element with 44 protons in the nucleus, which means the atomic number is 44, is ruthenium, chemical symbol Ru. The superscript to the left of the chemical symbol would be the mass number, which is the total number of protons and neutrons in the nucleus of that atom. We add the number of protons, 44, to the number of neutrons, 58, to get a mass number of 102. The left subscript is the atomic number, which is 44. The superscript to the right of the chemical symbol is the charge of the ion. We figure this out by adding up the negative and positive charges to get a net charge. There are 44 protons, each with a single positive charge for a total charge of +44. The number of electrons is 41, each with a single negative charge for a total charge of -41. We add +44 to -41 to get a net charge of +3. The symbol for this atom would be $^{102}_{44}$Ru$^{3+}$ (d) The element with 15 protons in the nucleus, which means the atomic number is 15, is phosphorus, chemical symbol P. The superscript to the left of the chemical symbol would be the mass number, which is the total number of protons and neutrons in the nucleus of that atom. We add the number of protons, 15, to the number of neutrons, 16, to get a mass number of 31. The left subscript is the atomic number, which is 15. The superscript to the right of the chemical symbol is the charge of the ion. We figure this out by adding up the negative and positive charges to get a net charge. There are 15 protons, each with a single positive charge for a total charge of +15. The number of electrons is 15, each with a single negative charge for a total charge of -15. We add +15 to -15 to get a net charge of 0. This is, therefore, a neutral atom. The symbol for this atom would be $^{31}_{15}$P.