Answer:
Atom X will accept electrons from atom Y
Step-by-step explanation:
The outermost shell of an atom is full when it contains 8 valence electrons (except for the first shell, which only contains 2 electrons). Therefore, any atom tends to accept electrons if it's very close to complete the shell with 8 electrons, or to donate electrons if it has only a few electrons in its outest shell.
In this case, we have:
- Atom X: 6 valence electrons --> it tends to accept electrons, since it needs only 2 of them to complete the shell
- Atom Y: 2 valence electrons --> it tends to donate electrons, so it has its outermost shell completed also
- Atom Z: 8 valence electrons --> it has no tendency in donate/accept electrons, since its outermost shell is already full
Therefore, atom Y will donate its 2 valence electrons to atom X, so that both of them have their outermost shell completed.