Fill in the Blank Question Each element has a unique number of
which is called the atomic number. For an electrically neutral atom, this number is also equa
the number of
present
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Which best describes the present-day universe? opaque, expanding very slowly, stars produce heavy elements transparent, expanding at an accelerated rate, stars produce heavy elements opaque, expanding at an accelerated rate, stars produce only hydrogen and helium transparent, expanding very slowly, stars produce only hydrogen and helium