Pre-note: I realize now the title of this thread is not quite what I wanted it to be but I can't edit it so whatever lol. It was created when I was originally going to create this thread to see only if hydrogen should be a halogen or alkali metal only until I later on discovered the argument for classifying it as a Group 14 or 4A element :laughing:.
I was reading up on why hydrogen was placed where it is on the periodic table and I came across various yet interesting arguments suggesting hydrogen should be considered more of a halogen or even a tetrel (carbon family/Group 14 or IVA). I remember often being told that hydrogen is more of an alkali metal (although has some unique properties) and I find this information to be quite interesting. Below I created tables comparing SOME (certainly not all, as this thread would be too long!) similarities and differences between hydrogen and the different groups it could be classified as/grouped with (is currently an ongoing debate).
What are your thoughts? Should hydrogen be considered more of an alkali metal, a halogen, a tetrel (carbon group), or considered classless (or in other words, its own class)?
A. Hydrogen is more of an alkali metal (is placed above lithium on periodic table)
http://www.colorado.edu/physics/2000/periodic_table/atomic_structure2.html#alkali(one website stating why hydrogen should be more classified as an alkali metal)
SOME of the similarities and differences between hydrogen and the alkali metals:
http://www.nature.com/nature/journal/v393/n6680/abs/393046a0.html (website discussing hydrogen [not] becoming an alkali metal under extremely high pressure [such as when placed on Jupiter], despite calculations suggesting otherwise)
B. Hydrogen is more of a halogen (is placed above fluorine on periodic table)
http://hydrogentwo.com/hydrogen-halogen.html(one website stating why hydrogen should be more classified as a halogen)
SOME of the similarities and differences between hydrogen and halogens:
http://www.google.com/imgres?
um=1&hl=en&sa=N&biw=1366&bih=681&authuser=0&tbm=isch&tbnid=dFd1CV_qpdf6YM:&imgrefurl=http://www.answers.com/topic/periodic-table&docid=PF_X0JzAEfdnuM&imgurl=http://content.answcdn.com/main/content/img/McGrawHill/Encyclopedia/images/CE498900FG0010.gif&w=640&h=352&ei=UEh7UKfxDYrg8ATJsYGwBw&zoom=1&iact=hc&vpx=647&vpy=282&dur=605&hovh=166&hovw=303&tx=155&ty=119&sig=112432762932647133545&page=2&tbnh=136&tbnw=248&start=15&ndsp=25&ved=1t:429,r:7,s:20,i:224(periodic table where hydrogen is grouped with the halogens)
http://onlinelibrary.wiley.com/doi/10.1002/open.201100015/full (this article discusses how hydrogen and halogen bonds are similar and different from each other)
C. Hydrogen should be considered more of a tetrel (is placed above carbon on the periodic table)
http://www.reed.edu/reed_magazine/summer2009/columns/noaa/downloads/CronynHydrogen.pdf(one document that states why hydrogen is more of a tetrel [carbon group]).
SOME of the similarities between hydrogen and the tetrel family, primarily carbon and silicone:
*values will differ source to source. I got these values from my textbook.
Hein, Morris, and Susan Arena. Foundations of College Chemistry. 13th ed. Hoboken, NJ: Wiley;, 2011. Print.
D. None of the above/Hydrogen should be considered its own unique group (has its own spot on the periodic table on periodic tables)
http://www.citycollegiate.com/positionofh.htm (one website that states why hydrogen should have its own place on the periodic table)
http://www.friendsmania.net/forum/2nd-year-chemistry-notes/25788.htm (one person's notes on hydrogen's similarities and dissimilarities with the mentioned groups above that I thought were worthy of mentioning)
Reasons why hydrogen is considered unique:
http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel_pre_2011/patterns/groupsrev1.shtml(periodic table with hydrogen in its own spot)
More information:
http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Descriptive_Chemistry/Main_Group_Elements/Group__1%3a_The_Alkali_Metals/Chemistry_of_Hydrogen(some basic hydrogen facts)
http://www.oup.com/uk/orc/bin/9780199236176/ch10.pdf(some information on hydrogen's unique chemistry)
https://fcserver.nvnet.org/~tisosky/FOV1-0004CBC5/FOV1-0005FB31/electronegativity_table_bw.jpg(Electronegativity periodic table chart)
http://www.vias.org/genchem/covbonds_12584_03.html (Information on compounds containing carbon and hydrogen [hydrocarbons]).
http://www.austincc.edu/emeyerth/polarity.html(information about ionic, polar covalent, and non-polar covalent bonds and a little about electron affinity).
http://aether.lbl.gov/www/tour/elements/stellar/stellar_a.html (information about formation of high mass elements and what happens inside of a star. Also talks about hydrogen being thought of as being the first element ever created according to the Big Bang Theory).
I was reading up on why hydrogen was placed where it is on the periodic table and I came across various yet interesting arguments suggesting hydrogen should be considered more of a halogen or even a tetrel (carbon family/Group 14 or IVA). I remember often being told that hydrogen is more of an alkali metal (although has some unique properties) and I find this information to be quite interesting. Below I created tables comparing SOME (certainly not all, as this thread would be too long!) similarities and differences between hydrogen and the different groups it could be classified as/grouped with (is currently an ongoing debate).
What are your thoughts? Should hydrogen be considered more of an alkali metal, a halogen, a tetrel (carbon group), or considered classless (or in other words, its own class)?
A. Hydrogen is more of an alkali metal (is placed above lithium on periodic table)
http://www.colorado.edu/physics/2000/periodic_table/atomic_structure2.html#alkali(one website stating why hydrogen should be more classified as an alkali metal)
SOME of the similarities and differences between hydrogen and the alkali metals:
Hydrogen and alkali metals alike | Hydrogen and alkali metals different |
Have 1 electron in valence shell | Hydrogen can either gain or lose an electron during reactions, whereas alkali metals only lose electrons during reactions |
Hydrogen can lose an electron in reactions, like alkali metals | Alkali metals can only form ionic compounds, whereas hydrogen can create both ionic and covalent compounds |
Valence shell configuration is Ns[SUP]1[/SUP] | Hydrogen is a gas at room temperature, whereas the alkali metals are solid at room temperature |
Can form halides | Hydrogen can be an oxidizing or a reducing agent, whereas alkali metals can only be reducting agents |
Are good "reducing agents" (hydrogen a reducing agent when combined with nonmetals) | Hydrogen's first ionization energy is much higher than the alkali metals (Hydrogen at about 1314 kJ/mol, Lithium [has highest first ionization energy of the akali metals] at about 520 kJ/mol) |
http://www.nature.com/nature/journal/v393/n6680/abs/393046a0.html (website discussing hydrogen [not] becoming an alkali metal under extremely high pressure [such as when placed on Jupiter], despite calculations suggesting otherwise)
B. Hydrogen is more of a halogen (is placed above fluorine on periodic table)
http://hydrogentwo.com/hydrogen-halogen.html(one website stating why hydrogen should be more classified as a halogen)
SOME of the similarities and differences between hydrogen and halogens:
Hydrogen and Halogens Alike | Hydrogen and Halogens Different |
Hydrogen can gain an electron in reactions, as halogens do in reactions. | Hydrogen has 1 electron in valence shell and halogens 7. |
Both act as negative ions when bonding with metals. | Hydrogen can either gain or lose 1 electron, halogens can only gain 1 electron. |
Hydrogen and halogens both are non-metals. | Halogens can have a large atomic radius, whereas hydrogen has a very small atomic radius. |
Molecules of both are diatomic (A[SUB]2[/SUB]). | Halogens have a valence electron configuration of Ns[SUP]n[/SUP], whereas hydrogen has an electron configuration of 1s[SUP]1[/SUP]. |
Both can form both ionic bonds and covalent bonds. | Hydrogen ions are unstable in water, whereas halogen ions are stable in water. |
http://www.google.com/imgres?
um=1&hl=en&sa=N&biw=1366&bih=681&authuser=0&tbm=isch&tbnid=dFd1CV_qpdf6YM:&imgrefurl=http://www.answers.com/topic/periodic-table&docid=PF_X0JzAEfdnuM&imgurl=http://content.answcdn.com/main/content/img/McGrawHill/Encyclopedia/images/CE498900FG0010.gif&w=640&h=352&ei=UEh7UKfxDYrg8ATJsYGwBw&zoom=1&iact=hc&vpx=647&vpy=282&dur=605&hovh=166&hovw=303&tx=155&ty=119&sig=112432762932647133545&page=2&tbnh=136&tbnw=248&start=15&ndsp=25&ved=1t:429,r:7,s:20,i:224(periodic table where hydrogen is grouped with the halogens)
http://onlinelibrary.wiley.com/doi/10.1002/open.201100015/full (this article discusses how hydrogen and halogen bonds are similar and different from each other)
C. Hydrogen should be considered more of a tetrel (is placed above carbon on the periodic table)
http://www.reed.edu/reed_magazine/summer2009/columns/noaa/downloads/CronynHydrogen.pdf(one document that states why hydrogen is more of a tetrel [carbon group]).
SOME of the similarities between hydrogen and the tetrel family, primarily carbon and silicone:
Hydrogen and Tetrels (primarily C and Si) Alike | Hydrogen and Tetrels Different |
Valence shells are half-filled (hydrogen = 1 out of 2, tetrels= 4 out of 8). | Hydrogen is gas at room temperature, whereas Group IVA/Group 14 elements are solid at room temperature. |
Electronegativity values are comparable (Hydrogen 2.1, Carbon 2.5, Si 1.8, etc.)*. | Hydrogen's valence electron configuration is 1s[SUP]1[/SUP], whereas the tetrels have a valence electron configuration of ns[SUP]2[/SUP]np[SUP]2[/SUP]. |
First ionization energy values are similar (Hydrogen at about 1314 kJ/mol, Carbon at about 1.088 kJ/mol)*. | Hydrogen is monovalent (1 valence electron), whereas the tetrels are tetravalent (4 valence electrons). |
Hydrogen and the tetrels can form covalent bonds. | Hydrogen can form both ionic and covalent bonds, whereas the tetrels can form only covalent bonds. |
Hydrogen and the tetrels (primarily Hydrogen and Carbon) have similar electron affinities (forming non-polar covalent bonds). | Various tetrels can come in the form of allotropes (carbon [ex. graphite, diamonds], silicone [amorphous, crystalline]) whereas hydrogen does not. |
Hein, Morris, and Susan Arena. Foundations of College Chemistry. 13th ed. Hoboken, NJ: Wiley;, 2011. Print.
D. None of the above/Hydrogen should be considered its own unique group (has its own spot on the periodic table on periodic tables)
http://www.citycollegiate.com/positionofh.htm (one website that states why hydrogen should have its own place on the periodic table)
http://www.friendsmania.net/forum/2nd-year-chemistry-notes/25788.htm (one person's notes on hydrogen's similarities and dissimilarities with the mentioned groups above that I thought were worthy of mentioning)
Reasons why hydrogen is considered unique:
- The most common isotope of hydrogen (protium) has only 1 proton and 1 electron, meaning it has no neutrons. Every other element has neutrons (not counting isotopes that are unstable).
- It can gain (more frequent) or lose electrons in reactions. Every other element either gains, loses, or shares electrons.
- It shares similar properties with multiple groups of the periodic table, as discussed above (thus is hard to classify under a specific, unlike other elements!).
- Due to its high re-activity, hydrogen can bond with almost all of the elements.
- Hydrogen is said to be the first element ever created, according to the Big Bang Theory.
http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel_pre_2011/patterns/groupsrev1.shtml(periodic table with hydrogen in its own spot)
More information:
http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Descriptive_Chemistry/Main_Group_Elements/Group__1%3a_The_Alkali_Metals/Chemistry_of_Hydrogen(some basic hydrogen facts)
http://www.oup.com/uk/orc/bin/9780199236176/ch10.pdf(some information on hydrogen's unique chemistry)
https://fcserver.nvnet.org/~tisosky/FOV1-0004CBC5/FOV1-0005FB31/electronegativity_table_bw.jpg(Electronegativity periodic table chart)
http://www.vias.org/genchem/covbonds_12584_03.html (Information on compounds containing carbon and hydrogen [hydrocarbons]).
http://www.austincc.edu/emeyerth/polarity.html(information about ionic, polar covalent, and non-polar covalent bonds and a little about electron affinity).
http://aether.lbl.gov/www/tour/elements/stellar/stellar_a.html (information about formation of high mass elements and what happens inside of a star. Also talks about hydrogen being thought of as being the first element ever created according to the Big Bang Theory).