SolveItClass 9 · NCERT

NCERT Solutions · Class 9 Science Journey Inside the Atom

33 questions · 19 still being checked

Pause and Ponder 8.13 (part 19 of 23)

  1. Exercise 8.13

    An atom electrons. number of neutrons in it. 150\displaystyle 150 Exploration|Grade 9\displaystyle 9
    NCERT’s answer
    Neutrons $\displaystyle 12$
    $\displaystyle 12$ neutrons.
    NCERT_Solution_Class9_Science_Ch8_PP_Q8-13
    The atom is neutral, so protons \(\displaystyle =\) electrons \(\displaystyle = 11\), which makes \(\displaystyle Z = 11\).
    The superscript gives the mass number, \(\displaystyle A = 23\).
    \(\displaystyle \text{neutrons} = A - Z = 23 - 11 = 12\)
    (\(\displaystyle Z = 11\) with \(\displaystyle A = 23\) is sodium.)