pussycatjayne - 19-10-2011 at 14:09
Hi I've been given this question and I've been looking at it for hours without any joy so alas I need your expertise to help me
"Q: Sodium Bromide, the symbols for the elements in this compound are 23Na, 79Br and 81Br
Write an equation to show the reaction between sodium and bromine to form sodium bromide, and explain what is happening during the reaction to the
valance electrons."
Me: I really want to be able to understand this as well as get it right so if someone could also just give me a bit of lamens terms explanation so I
can understand how the correct answer was achieved that'd be fabulous
Charotte xx
[Edited on 19-10-2011 by pussycatjayne]
SmashGlass - 19-10-2011 at 15:57
1) Do your own damn homework!
2) Since I’m Dr Nice Guy today…
Sodium. (Group I) 1 valence electron.
Electron configuration. 1s^2, 2s^2, 2p^6, 3s^1. Or [Ne] 3s^1. Sodium contains a total of 11 electrons. [Add up the numbers in superscript[^] "because
I wrote this in word originally", or electrons in each shell orbital group, remember there are 3 “p” orbitals and only 2 electrons can only fit in
one orbital zone.]
The elemental coding “Na” comes from the Swedish abbreviation Natrium the Swedish name for the element Sodium by Jons Jakob Berzelius. Although
discovered by Sir Humphrey Davy (Great Britain) in 1806 through the electrolysis of soda ash. Eventually he called the element Sodium in the English
language, since Davy did not take a liking to his original name for the element “Sodagen”.
In German soda ash or caustic soda was called natronlauge, being the name-sake of the element for Berzelius.
Ref - http://www.chemicool.com/elements/sodium.html
Bromine (Group VII, or Group XVII if you want to use all the periodic table) 7 electrons in the outer shell (the valence shell).
Electron configuration. [Ar] 3d^10, 4s^2, 4p^5. Just add up the electrons in the 4th shell.
Molecular Bromine exists as a diatomic molecule in the form of Br2.
The naturally stable isotopes of Br are 79Br and 81Br, in approximately a 1:1 ratio, a hallmark signature for the presence of Br in molecules when
using mass spectrometry (MS).
The general reaction scheme for sodium metal reacting with liquid/gaseous bromine with the correct stoichiometry would be:
2 Na (s) + Br2 → 2 NaBr + energy (heat)
The valence orbital overlap is rather poor between these two elements due to a slight electronic mis-match when compared to that of NaCl or KBr (which
are both more stable salts then NaBr). If you look at the placement of the two elements on a periodic table one will see that Sodium is a whole row
above Bromine. It is a known method to release bromine from an aqueous solution of NaBr by bubbling chlorine gas (Cl2) through the solution releasing bromine gas which escapes the water when warmed to around 80ºC.
You can try to work out that reaction yourself. It’s somewhat similar to the one above.
Hope this helps a little bit.
But I wouldn’t want to see this plagiarized as YOUR homework, thank you.
White Yeti - 19-10-2011 at 17:05
I agree with Smash.
However, I think it might be a good idea to call an administrator to move this thread to the beginnings section where it belongs. You're not used to
the format of the forum yet (completely acceptable). For future reference, schoolwork questions should go in the "beginnings" section. Just don't
abuse the forum, people here get cranky when homework questions like these show up on a forum like this.