An ion that consists of 7 protons, 9 neutrons, and 10 electrons has a net charge of A) 2–
B) 2+
C) 3+
D) 3–
The answer is D. Why the answer is not A but D? Can you explain?

The image compares the arrangement of electrons in two different neutral atoms. a figure labeled atom q has a shaded sphere at the center of three concentric circles. the innermost circle has two black spheres. the middle circle has six black spheres. to the left of this figure is another figure labeled atom p. atom p has a shaded sphere at the center of three concentric circles. the innermost circle has two black spheres. the middle circle has seven black spheres. which of the following best explains the position of the two atoms in the periodic table?