Answer
$\Delta m = 0.1123553 u$
Work Step by Step
To find the mass defect,
$\Delta m = (7 m_H + 7m_n - m_N) $
$\Delta m = (7 \times 1.007 825 0 u) + (7 \times 1.008 664 9 u) - 14.003 074 0 u $
$\Delta m = 0.1123553 u$
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