Physics – 5.1.2 The nucleus | e-Consult

(a) The nuclide notation for Potassium is ₁₉³⁹ K.

(b) Sample A, which gives a positive result for alpha decay, contains an unstable nucleus that has emitted an alpha particle (⁴He). This means the nucleus has a high number of protons and neutrons, and the alpha decay has reduced both. Sample B, which gives a positive result for beta decay, contains an unstable nucleus that has emitted a beta particle (an electron). This means the nucleus has too many neutrons relative to protons, and the beta decay has converted a neutron into a proton, increasing the atomic number.

(c) The element represented by the nuclide ₈¹⁶ O is Oxygen (O). The atomic number (Z=8) identifies it as Oxygen, and the mass number (A=16) identifies it as the common isotope Oxygen-16.