## Chemistry: Molecular Approach (4th Edition)

(a)$\underline{_{29}^{63}\text{Cu}}$ (b)$\underline{_{29}^{65}\text{Cu}}$ (c)$\underline{_{19}^{40}\text{K}}$ (d)$\underline{_{18}^{40}\text{Ar}}$
(a) The number of neutrons of copper is 34. The atomic number of copper is 29 from the periodic table. The number of protons is given by the atomic number. So, the number of protons is 29. The relation between the mass number, the number of protons, and the number of neutrons is as follows: $A=\text{Number of protons}+\text{Number of neutrons}$ Here, A is the mass number. Calculate the mass number as follows: \begin{align} & A=29+34 \\ & =63 \end{align} The notation for the isotope is as follows: $_{Z}^{A}\text{X}$ Here, A is the mass number, Z is the atomic number, and X is the chemical symbol. So, the isotopic notation for the copper isotope with 34 neutrons is as follows: $\underline{_{29}^{63}\text{Cu}}$ The isotopic symbol is $\underline{_{29}^{63}\text{Cu}}$. (b) The number of neutrons of copper is 36.The atomic number of copper is 29 from the periodic table. The number of protons is given by the atomic number. So, the number of protons is 29. The relation between the mass number, the number of protons, and the number of neutrons is as follows: $A=\text{Number of protons}+\text{Number of neutrons}$ Here, A is the mass number. Calculate the mass number as follows: \begin{align} & A=29+36 \\ & =65 \end{align} The notation for the isotope is as follows: $_{Z}^{A}\text{X}$ Here, A is the mass number, Z is the atomic number, and X is the chemical symbol. So, the isotopic notation for the copper isotope with 36 neutrons is as follows: $\underline{_{29}^{65}\text{Cu}}$ The isotopic symbol is $\underline{_{29}^{65}\text{Cu}}$. (c) The number of neutrons of potassium is 21. The atomic number of potassium is 19 from the periodic table. The number of protons is given by the atomic number. So, the number of protons is 19. The relation between the mass number, the number of protons, and the number of neutrons is as follows: $A=\text{Number of protons}+\text{Number of neutrons}$ Here, A is the mass number. Calculate the mass number as follows: \begin{align} & A=19+21 \\ & =40 \end{align} The notation for the isotope is as follows: $_{Z}^{A}\text{X}$ Here, A is the mass number, Z is the atomic number, and X is the chemical symbol. So, the isotopic notation for the potassium isotope with 21 neutrons is as follows: $\underline{_{19}^{40}\text{K}}$ The isotopic symbol is $\underline{_{19}^{40}\text{K}}$. (d) The number of neutrons of argon is 22. The atomic number of argon is 18 from the periodic table. The number of protons is given by the atomic number. So, the number of protons is 18. The relation between the mass number, the number of protons, and the number of neutrons is as follows: $A=\text{Number of protons}+\text{Number of neutrons}$ Here, A is the mass number. Calculate the mass number as follows: \begin{align} & A=18+22 \\ & =40 \end{align} The notation for the isotope is as follows: $_{Z}^{A}\text{X}$ Here, A is the mass number, Z is the atomic number, and X is the chemical symbol. So, the isotopic notation for the argon isotope with 22 neutrons is as follows: $\underline{_{18}^{40}\text{Ar}}$. The isotopic symbol is $\underline{_{18}^{40}\text{Ar}}$.