Why can sulphur lose 6 electrons while magnesium can't gain 6?

In summary, the conversation discusses the ion charges of sulphur and magnesium when bonding with other atoms. The speaker suggests that magnesium's lower electronegativity may explain its consistent 2+ charge, while sulphur's high electronegativity and desire to complete its octet may explain its varying charge. However, it is noted that oxidation numbers are simply a method of bookkeeping and do not accurately represent the actual charge on an atom. Ultimately, magnesium is most stable as Mg+2 and sulphur as S-2 in ionic compounds.
  • #1
dontdisturbmycircles
592
3
Hello,

I am fighting with a problem from grade 11 chem right now.

The problem is why when sulphur bonds to other atoms, its ion charge often becomes 6+ or 2- while magnesium will always form an ion of charge 2+.

I think I have an answer but am not sure. Is it because magnesium has a lower electronegativity and is less able/willing to attract extra elections? but then I have the paradox of why sulphur would be willing to lose 6(!) electrons with such a high desire to fill its last two orbitals and complete its octet (high electronegativity). :mad:
 
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  • #2
Sulfur never loses 6 electrons to form a stable ionic compound. Sulfur can however have a +6 oxidation state in compounds such as H2SO4. Realize that oxidation numbers are simply part of a "bookeeping" method devised by humans to keep track of which chemical species are being oxidized and reduced. Oxidation numbers do not represent the actual charge on an atom.

With regards to ionic compounds, Mg is most stable as Mg+2 and S as S-2.
 
  • #3


Hello,

Thank you for bringing this question to my attention. The reason why sulphur can lose 6 electrons while magnesium cannot gain 6 is due to their electron configurations.

Sulphur has an electron configuration of [Ne]3s²3p⁴. This means that its outermost energy level, the valence shell, has 6 electrons. In order to achieve a stable octet (8 electrons in the valence shell), sulphur can either gain 2 electrons or lose 6 electrons. However, gaining 2 electrons would require a significant amount of energy, as it would have to overcome the strong repulsive forces between the electrons in the same energy level. Therefore, it is more energetically favorable for sulphur to lose 6 electrons and form a 2- ion.

On the other hand, magnesium has an electron configuration of [Ne]3s². Its valence shell only has 2 electrons, making it easier for magnesium to lose those 2 electrons and achieve a stable octet. Gaining 6 electrons would require a significant amount of energy, as it would have to overcome the strong repulsive forces between the electrons in the same energy level. This is why magnesium will always form a 2+ ion, as it is more energetically favorable.

In summary, the ability of an atom to gain or lose electrons depends on its electron configuration and the amount of energy required to do so. In the case of sulphur and magnesium, their electron configurations make it more favorable for sulphur to lose 6 electrons and for magnesium to lose 2 electrons in order to achieve a stable octet. I hope this explanation helps clarify the concept for you. Keep up the good work in your chemistry studies!
 

Related to Why can sulphur lose 6 electrons while magnesium can't gain 6?

1. Why does sulphur have the ability to lose 6 electrons?

Sulphur has 16 electrons in its outermost energy level, which is two electrons short of having a full octet. Losing 6 electrons would result in a more stable electron configuration, as it would then have a full octet of electrons in its outermost energy level.

2. How does sulphur lose 6 electrons?

Sulphur can lose 6 electrons through the process of oxidation, where it transfers electrons to another element or compound. This results in sulphur having a more positive charge, as it has lost negatively charged electrons.

3. Why can't magnesium gain 6 electrons?

Magnesium has 12 electrons in its outermost energy level, which is only two electrons away from having a full octet. However, gaining 6 electrons would result in a more unstable electron configuration, as it would have a full octet in its outermost energy level but also have a large number of negatively charged electrons.

4. What determines an element's ability to lose or gain electrons?

The ability of an element to lose or gain electrons is determined by its number of valence electrons and its position on the periodic table. Elements with fewer valence electrons are more likely to lose electrons, while elements with more valence electrons are more likely to gain electrons in order to achieve a full octet in their outermost energy level.

5. Can sulphur or magnesium change the number of electrons they can lose or gain?

No, the number of electrons an element can lose or gain is determined by its atomic structure and cannot be changed. However, elements can form ions with different charges by losing or gaining different numbers of electrons.

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