Zinc, Cadmium and MercuryTable of contentsGroup 12 of the Periodic Table include Zinc, Cadmium and Mercury. These metals tend to have properties characteristic of elements with full subshells, which includes having low melting and boiling points (due to the weak metallic bonding of the ns2 electrons) and charges of +2 or +1. Introduction: The Properties of Group 12Zinc (Zn) is a blue-white metal of moderate strength, hardness and ductility. Zinc is one of the least common elements and is mostly produced through electrolysis of aqueous zinc sulfate. About one third of all metallic zinc is used to manufacture galvanized nails. Because of its low melting point and its ability to form bonds with iron or steel, it serves to coat the metal and protect it from corrosion. Metallic zinc is also used to make dry cell batteries.
Zinc has many unique characteristics. For example, its vapor burns in air with a green flame, forming zinc oxide. Zinc oxide is a common zinc compound that is used in paints, cosmetics, plastics and more. Metallic zinc reacts with weak acids very slowly. Sulfur has a strong affinity for zinc. When heated, the two powders react explosively to form zinc sulfide. Zinc sulfide is used to make television screens and fluorescent light bulbs. Zinc also reacts with halogens. However, as the electronegativity decreases among the halogen group, the reactivity with zinc decreases. Thus, the most electronegative of the halogens (Fluorine) reacts to zinc violently, while the less electronegative halogen (Iodine) only generates a small amount of heat. Interestingly, properties of zinc are strongly affected by impurities such as lead, cadmium and iron. Also, zinc is most often used as a reducing agent in chemical reactions and it forms complex ions with ammonia and cyanide ions. Zinc plays a huge part in the production of alloys. One of the best known zinc alloy is brass, which contains between 55-95% copper. Zinc also takes part in manufacturing solder, which has a relatively low melting point. Solder is used to join electrical components, as well as pipes and other metals. Cadmium (Cd) is a unique metal that was first found in zinc dust. Cadmium usually occurs in zinc ores and it even less common than zinc. Cadmium has never been found by itself in nature; it is always combined with other elements, usually in oxycarbonate and cadmium oxides. Cadmium is more volatile than zinc and it is a fairly soft, white metal. It also has lower melting points and boiling points than those of zinc.
Cadmium is often used for electroplating, which is done to make small parts on radios, nuts and screws. Cadmium is used in making alloys such as aluminum solders and control rods for nuclear reactions. Like zinc, it forms complex ions with ammonia and cyanide ions. Interestingly, cadmium hydroxide is more basic than zinc hydroxide. Cadmium burns in air to form brown cadmium oxide. Although cadmium is most often found in the +2 oxidation state, the +1 oxidation state can found by dissolving cadmium in a solution of cadmium chloride and aluminum chloride. This forms Cd22+, which is similar to the Hg22+ in mercury (I) chloride.[1] Cadmium is also toxic to humans. Poisoning occurs by inhaling its fumes or ingesting cadmium compounds. Symptoms of cadmium poisoning include soreness in the chest, difficulty breathing, abdominal pain, nausea and vomiting. Mercury (Hg) was one of the first known metals to man. In the past, many alchemists tried to turn Mercury into silver or gold. It is a silvery white liquid and below its freezing point becomes a white malleable metal. Mercury is the only metal that remains liquid at room temperature and is nicknamed quicksilver.
Most metals dissolve in Mercury. Mercury is not oxidized by air at room temperature, but when heated slowly it forms HgO. Mercury also has little tendency to combine with oxygen, which means that HgO is thermally unstable. Most mercury compounds are water soluble and many compounds are covalent. Mercury is also used in amalgams, which are mercury alloys. Amalgams are typically used for commercial industry such as silver dental fillings. Mercury does not react with most acids. Interestingly, oxidizing acids such as concentrated sulfuric acid or nitric acid dissolve it to give sulfate and nitrate salts. Mercury is also very toxic to humans. Inhalation of mercury vapor leads to severe poisoning and it can be absorbed through unbroken skin. Symptoms of mercury poisoning includes salivation, ulceration, diarrhea, tremors, nausea and headaches. Interestingly enough, Mercury (II) chloride is a violent poison, however, Mercury (I) chloride is a medicine. Mercury was used in thermometers because of its abilities of having a uniform expansion rate and the fact that it does not wet glass. Generally the mercury (I) compounds are fairly stable in comparison with other forms of mercury.
In the past, mercury was used in thermometers, however, it is no longer used due to health hazards. These are some properties of group 12 metals
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ProblemsHighlight for the answers. 1. ZnO + CO →Zn + CO2 2. CdCl2 → Cd2+ + 2Cl- 3. HgCl4 →HgCl2 + 2Cl- 4. What is the electron configuration of Zn2+? Zn2+= [Ar] 3d10 (Zinc is oxidized so electrons are removed from the 4s orbital) Contributors
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Zinc is being compared with a penny. 
Zinc is used to galvanize nails.
Brass
Cadmium 
Nickle Cadmium Battery
Module Title: Zinc, Cadmium, and Mercury
Module Author(s): Tabatha Schnelker
Specific Questions:
This module was somewhat informative. The table was placed very nicely at the end for a final summary. I believe there are no errors or statements I consider unjustifiable. The length of the module is rather short, but it is very clean and spaced out nicely. It does not look jarring on the computer screen.
Recommendation:
Publish with major revisions
Synopsis: Pretty much this was just a review of characteristics of Zinc, Cadmium, and Mercury. Zinc can be explosive with Sulfer and burns green. It has a low melting point, and bonds with steel. Cadmium is poisonous to the body when inhaled. Like zinc, it has a low melting point, but cadmium is pretty soft and a white metal. Mercury is highly important. It is a liquid at room temperature and toxic to humans. Mercury is the densest of the three.
Details: The most critical problem I have with this piece are the paragraphs. It seems to me you are copying out of a textbook and just plopping it in there. You also have a lot about medical relevance. This is fine, but separate/delete them from the paragraph containing information about its reactivity, bonding behaviors, etc. I get a strong textbook feeling, and it barely helps me understand the differences between the three and why they are important in chemistry.
Specific Points to fix: 1. Get rid of the textbook feeling. Add bullet points or make smaller paragraphs.
2. Add more conceptual problems, either multiple choice or free response just like midterms and finals do.
3. A video about the characteristics for all three metals would be very helpful.
4. Your figure is very elementary. Find something more specific. Pictures of the metals in different states and how they burn would be all better than your figure you have right now.
5. I like the highlight for the answers. A link to the other source you used besides the general chem. Textbook would be nice, and links other than Wikipedia would be helpful as well.
Module Title: Zinc, Cadmium, and Mercury
Module Author(s): Tabatha Schnelker
Specific Questions:
1) The module falls well within the scope of the journal.
2) Most if not all statements presented are supportable by physical evidence and references.
3) As far as I can see the facts and logics of this module remain correct.
4) The length could be a little longer.
5) Informative, but could be longer.
6) Very appropriate figures, helps to understand. More content would require more figures.
7) Longer paragraph may have warranted changes, but it is fine as it stands.
Recommendation: Publish with minor revision.
Synopsis: Zinc is useful as a reducing agent, and is valuable due to its scarcity and usefulness for the metallurgical processes. Cadmium is used in nuclear reactions, and alloy formation, and is even less common than the zinc in terms of scarcity. Mercury is useful as the only metal element in liquid form at room temperature, but presents a grave health hazard to humans due to its toxic nature. All three metals are useful in the industrial processes.
Details: The overall quality of the module meets the standards of chemistry wiki, but there is still room for improvements. One of the most glaring errors is some grammatical problems along the second paragraph dealing with cadmium. Also, the paragraph format has its own detractors. It may have been better to post the figure and its explanations between the paragraphs, so that they may better serve their purpose. However the overall quality remains decent the way it is.
Specific Points to fix:
1. Check grammar in paragraphs.
2. Build more figures to assist with explanations.
3. More real-life examples may be needed.
4. Longer details regarding chemical reactions.
5. More chemistry and explanations for physical properties of the metals.
Module Title: Zinc, Cadmium, and Mercury
Module Author(s): Tabatha Schnelker
Specific Questions:
1) yes
2) statements are justifiable
3) no
4) The length could be a little longer.
5) Informative but very short
6) Very appropriate figures
7) More information would have been helpful
Recommendation: Publish with minor revision.
Synopsis: Group 12 of the periodic table includes Zn, Cd and Hg. These metals have low melting point and boiling points. Zinc is often used as reducing agent, cadium occurs in zinc ores, and mercury is the only metal that remains liquid at room temperature.
Details: Short, could use more details, and contains some grammatical errors.
Specific Points to fix:
1. Check grammar in paragraphs.
2. Provide more information about the metals and trends
3. Pictures of these metals
4. History and background could be useful
5. Better practice questions and provide answer key.
Module Author(s): Tabatha Schnelker
Specific Questions:
(1) Does the module fall within the scope of the Journal? Yes
(2) Are any statements made which you consider unjustifiable? No
(3) Are there any apparent errors of fact or logic? No
(4) Is the length of the module appropriate? Yes... but a bit short compared to other modules I've seen
(5) Is the summary informative? Yes
(6) Are the figures appropriate? Yes
(7) Is the module format useful? Yes
Recommendation:
Select one: 2) Publish with minor revisions.
Synopsis: Zn, Cd, and Hg are in group 12 on the periodic table. These elements share similar characteristics such as their low melting points and low boiling points. All of these metals are unique in their own way, such as mercury being the only metal that is liquid in room temperature, and zinc being needed in our human body.
Details: I think it's perfectly fine. The module covers all the major areas of these elements, and mentions everything important. However, if you could, adding a few more info on this subject wouldn't hurt either. Overall though, I still say its fine.
Specific Points to fix:
1. Add some pictures. What do they look like?
2. Provide an answer key
3. You could add some info on its trends in the periodic table
4. Check grammar
5. You could include some more outside links