Ignoring small electron binding energies and the very small mass of the neutrino, show that the mass of a nucleus increases when it decays by electron capture if the Q-value of the decay is less than m_ec² ? 0.511 MeV. Verify that this is the case for the electron capture decay of the longest-lived isotope of technetium:

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97 Тс + e 43 Tc + e¯ →% 97 42 Мо + Ve