I believe it it a chemical reaction...hope this helps and you make a good grade :
3 Chlorine ions are required to bond with one aluminum ion.
In ionic bonds, metals atoms loses all its outermost shell electrons to form a cation. While, non metal atoms gains however many electrons in order to make its outermost electron shell be 8 (or 2 if there's only one shell).
Therefore, form the periodic table, we can see that aluminum has a atomic number of 13, which makes its electron arrangement be 2,8,3. So, in order to form a aluminum ion, an Al atom must lose 3 electrons. On the other hand, Chlorine has a atomic number of 17, which means it has the electron configuration of 2,8,7. It has to gain only 1 electron to have 8 outermost shell electron.
Thereofre, 3 Chlorine atom are required to gain all 3 electrons given out by just 1 aluminum ion.
The factor in determining the average atomic mass of an element is:
B or 2 relative abundance of each isotope because the by looking at how many protons , electrons and neutrons the most isotope is of the element has relative abundance.
Answer:
Elements form compounds to satisfy the octet rule. Noble gasses never form compounds because they already satisfy the octet rule.
Explanation:
The octet Rule is the theory that an element will attempt to gain a valence of 8 by binding with another element in it's vicinity. This can happen in a variety of ways, but the main thing to remember is that they will take the "shortest path" to 8(I.e an element will sometimes lose an electron or 2 if it has a valence 1 or 2 to loop back around to 8, while an element with a valence of 6 or 7 will attempt to gain 2 or 1 electrons).
Valence of elements can be counted by group in the image attached.
Group 1 has a valence of 1, Group 2 has a valence of 2, then we move to group 13 which has a valence of 3, group 14 has a valence of 4, group 15 has a valence of 5, group 16 has 6, group 17 has 7, and group 18 is the noble gasses which have 8.