Question

1. which of the following statements is (are) true? $_6^{14}c$ and $_7^{14}n$ are isotopes of each other because their mass numbers are the same. none of these are true. $_8^{18}o^{2 - }$ has the same number of electrons as argon. $_8^{16}o$ and $_9^{19}f$ have the same number of neutrons.

Explanation:

Step1: Recall isotope definition

Isotopes are atoms of the same element with different mass - numbers. Since \(_{6}^{14}C\) and \(_{7}^{14}N\) are different elements (different atomic numbers), they are not isotopes.

Step2: Calculate electrons in \(_{8}^{18}O^{2 -}\)

Oxygen has atomic number \(Z = 8\). \(_{8}^{18}O^{2 -}\) has \(8+2=10\) electrons. Argon has atomic number \(Z = 18\) and 18 electrons. So \(_{8}^{18}O^{2 -}\) does not have the same number of electrons as Argon.

Step3: Calculate neutrons in \(_{8}^{16}O\) and \(_{9}^{19}F\)

For \(_{8}^{16}O\), number of neutrons \(n_O=16 - 8=8\). For \(_{9}^{19}F\), number of neutrons \(n_F=19 - 9 = 10\). They do not have the same number of neutrons.

Answer:

none of these are true