Look at the diagrams below, showing mystery element A and mystery element D. How many valence electrons does mystery element A contain? Based on this, would it want to gain or lose electrons? Why is this? How many valence electrons does mystery element D have? Based on this, would it want to gain or lose electrons? Why is this?

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates

it's c (engineer's do their work with mechanical stuff not on any living being)