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Q6 : This is not taught in our school...1/5 or 4/5 why only by 5?
Q17 :
A: Mg
B: Al
C: Si
D : P
Q18 :
C : 1090 2350 4610
N : 1400 2860 4590
F : 1680 3370 6040
Na : 494 4560 6940
Q27 :
p = 43 e = 43 n = 56
This is true, but this is under the circumstance where Nitrogen forms 3 bonds and Sulfur forms 2 bonds. Sulfur does form two bonds with nitrogen in the structure displayed in question and hence it does have two lone pairs of electrons like you said. But if you look at the Nitrogen it only forms a total of two single bonds (one with each atom of sulfur) and not 3 bonds like how it is supposed to. So out of the 5 valence electrons in nitrogen 2 are used for bonding leaving 3 electrons free. Now this is where I'm really confused as we now have 1 lone pair and one electron in the outer shell ??Look at the groups in which Nitrogen and Sulfur reside.
Nitrogen is in group 5 and Sulfur in group 6.
That means Nitrogen has 5 electrons in its outer-shell, and Sulfur, 6.
The number of bonds an atom can form is,
No of bonds = Full valence shell - Number of valence electrons
For example, nitrogen already has 5 electrons, it needs 3 more to achieve a noble gas structure. So it will form 3 bonds.
The above formula works the same way,
No of bonds in N = 8 - 5 = 3
So with that in mind, Nitrogen can form 3 bonds and Sulfur can form 2.
The next thing to note, is that each bond will have two electrons.
Since nitrogen needs to form 3 bonds, it will need 6 electrons.
Sulfur needs to form 2 bonds, so it will need 4 electrons.
Out of the 8 electrons that can exist in the outer-shell,
-Nitrogen needs 6, which leaves 2 electrons not participating in any bond.
-Sulfur needs 4, which leaves 4 not participating in a bond.
A lone pair = 2 electrons not participating in a bond.
Nitrogen therefore has 1 lone pair and Sulfur has 2.
Hope that helped you!
That means 1 lone pair and 1 free radical. We are not asked for free radical so ignore that. Hence 1 lone pair on nitrogen.
Thanks a lot sir.
I am not sure if this is correct. Wait till Metanoia checks my answer.
This is what the Hess Cycle would look like (Teacher showed it to me):
MgO is almost insoluble ( due to high L.E).
Also due to no H2 bond in MgO.
a molecule of H2 has two hydrogen atoms so:
2Mg(NO3)2 ----> 2MgO + 4NO2 + O2
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