How many more neutrons would be in an isotope of sulfur-31 than a normal atom?: A. +1 B. +15 C. +16 D. -1​

-1 (D)

Explanation:

Looking at a periodic table, sulfur usually has an atomic mass of 32. It has 16 protons, so it usually has 16 neutrons.

From this isotope, it has an atomic mass of 31. It has 16 protons, so in this example there are 15 neutrons.

this means there is one less neutron than normal in this isotope.

Hope this helps! Let me know if you have any questions :)

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer