Help! 3 Chemistry Questions

[pink84]

Can someone enlighten these questions?

1. What ion charge do you expect for the atomic number 13?

I thought +3 because the outermost shell has 3 electrons.
However, the answer says -5.

2. Rank the atom from the lowest boiling point to highest?

F,Cl,Br,I

If I rank this order with the electronegativity, am I wrong?
So, I thought the order was F>Cl>Br>I


3. alcohol < aldehyde< ester< carboxylic acid
Is it the right order of acidity?

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[Kaxa2000]

1) The last valence shell has 3 electrons in it meaning it needs 5 more to have a full valence shell which gives it a -5 charge. If you look at the periodic table at the atom which atomic number 13(Al)....the atom next to it has -4(Si) charge and next to that atom is -3(P) charge and so on.

2) The list you have is right but you should order them according to atom size....the larger the molecule the the higher the boiling point will be because of the greater the attraction will be among molecules (london dispersion forces).

3.) Carboxylic acid , alcohol, aldehyde, ester

Think of ARIO - Atom, Resonance, Induction, Orbital (In order of importance)

From highest to lowest-

Carboxylic acid - has a hydrogen that is directly connected to a highly electronegative atom AND has resonance stabilization so that when the hydrogen leaves it will be able to stabilize itself.

Alcohol - the hydrogen is directly connected to a highly electronegative atom

Aldehyde - There is a polar C-O bond. The electronegative O draws electrons away from the C which draws electrons away from the C-H bond in order to stabilize itself. This is induction.

Ester - There is induction created by the oxygen atoms




I'm not 100% on my answers...wait for another answer for confirmation...I had to review a bit.

 

[uncbiograd]

agree with kaxa on #1 and 2.

anyone with more information on 3? i believe alcohols and aldehydes are both less acidic than water, but that doesn't tell me much..

 

[SYPHARMACY]

For 1, how did u know that the atom with atomic number 13 had an outermost valence shell with 3 electrons without looking at the periodic table.?

Can someone enlighten these questions?

1. What ion charge do you expect for the atomic number 13?

I thought +3 because the outermost shell has 3 electrons.
However, the answer says -5.

2. Rank the atom from the lowest boiling point to highest?

F,Cl,Br,I

If I rank this order with the electronegativity, am I wrong?
So, I thought the order was F>Cl>Br>I


3. alcohol < aldehyde< ester< carboxylic acid
Is it the right order of acidity?

 

[coolboy16]

I still think for number 1 the answer should be +3. Because aluminum has the tendency to lose 3 electrons to make a complete octet. That's how it normally behaves. Because its a metal.

If you look at it this way , Na has 1 electron in its outermost shell ; it will not take 7 electrons and become octet. Rather more feasible for it is to lose the valence electron.

 

[waterloggedfrog]

You can figure out how many electrons it has by doing it's quantum numbers, for something with 13 electrons it would be 1s2,2s2,2p6,3s2,3p1, since the last p and s subshell has 3 electrons that'd be how many it has in it's outter shell. It needs 5 more electrons to fill the p subshell.

 

[pharmRxn]

the first question is covered in collin packet. his answer is +3.
i am confused. i am not sure which answer is correct.
i can see that losing 3 electrons will require a lot of ionization energy, so the -5 seems better than the +3. it is better because the p orbital contains 1 electrons and this makes it easier for the other electrons to come in and fill the orbital to make it octet.

 

[pharmRxn]

I still think for number 1 the answer should be +3. Because aluminum has the tendency to lose 3 electrons to make a complete octet. That's how it normally behaves. Because its a metal.

If you look at it this way , Na has 1 electron in its outermost shell ; it will not take 7 electrons and become octet. Rather more feasible for it is to lose the valence electron.

the Na has 1 electron on its S orbital, so if it wants to gain electrons then it will gain only 1 electron, not 7. it can lose an electron easily to become octet because when the P orbital is filled with 6 electrons it will take lots of ionization energy to remove more electrons from it.

 

[coolboy16]

You can figure out how many electrons it has by doing it's quantum numbers, for something with 13 electrons it would be 1s2,2s2,2p6,3s2,3p1, since the last p and s subshell has 3 electrons that'd be how many it has in it's outter shell. It needs 5 more electrons to fill the p subshell.

but that is how aluminum tends to do . It loses the electron from the p orbital which is very easy for it. instead of gaining 5 more electrons. and always remember that metals form cations and nonmetals anions. I have been doing this for long. i am pretty sure +3 is the oxidation state of Al.

 

[tealish]

It should be Al3+, which is a pretty common cation. It's a metal, with a tendency to lose its electrons. Al5-? That looks all sorts of wrong.