Zinc is one of the transition earth metals which has a lustrous bluish-white colour. The zinc symbol is represented as Zn. The Zn atomic number is 30. The abundance of the zinc element is estimated at almost 65 grams for every ton of the Earth’s crust. The word ‘zinc’ has a German origin whereas its exact derivation goes beyond the Persian word ‘sing,’ which means stone.
Zn in chemistry is a very important element and has several chemical properties.
Zinc is considered one of the strongest reducing agents
Zn + 2HCl → ZnCl2 + H2
Burning zinc gives off a blue-green flare
The chemical reaction of zinc oxide is given by:
2Zn + O2 → 2ZnO
Zinc consist of five different natural stable isotopes
These isotopes include; 64Zn, 66Zn, 67Zn, 68Zn and 70Zn
Zinc has the lowest melting point after Cadmium and Mercury among all the transition metals
Zinc does not react with water directly. However, metallic zinc can react with oxygen present in the air in the presence of water vapour and thus, form zinc hydroxide.
Zn + 2H2O → Zn(OH)2 + H2
Zinc is one of the heavily used metals within the industry. Here is a list of some of the applications of zinc:
The majority of the zinc is used in the manufacturing of zinc oxides as well as creating roofing materials
Zinc oxides are mainly used as an additive to rubbers for the production of tires. This helps to withstand higher temperature as well as prevent any unnecessary wear and tear
Zinc is also used in galvanizing other metals such as iron and steel. It prevents iron from rusting. On the other hand, galvanized steel is mainly used in manufacturing vehicles
Alloys of metals are also formed using zinc. Some of the examples include nickel silver, brass, and even aluminium solder
Zinc is also used in the production of die-casting. It plays an integral part in electronic hardware.
Zinc oxide has also found its way into cosmetics, inks, pharmaceuticals, and even plastics
Zinc sulfide is used for making fluorescent lights, x-ray screens as well as luminous paints
Biological Significance of Zinc
The zinc atomic structure plays an integral role in every other living organism. In fact, almost 20 metalloenzymes have an active site formed through zinc. About 2.5g of zinc is present in an average human body, whereas we consume almost 15 milligrams per day. Some of the most common sources of zinc in food include beef, lamb, sunflower seeds, herrings and cheese.
On the contrary, zinc has carcinogenic properties too. Inhaling zinc (II) oxide can cause ‘zinc chills’ or commonly known as ‘oxide shakes.’
Some of the most astounding physical properties of zinc include:
At normal room temperature, it remains brittle with a crystalline state
One of the properties of zinc is that when heated between 110oC to 150oC, it becomes malleable and ductile
Zinc is highly reactive with dilute acids causing the release of hydrogen
Zinc also shows its reactive properties while combing with oxygen or any other non-metal
It is imperative to understand that the majority of the zinc compounds are widely used in organic synthesis. Below is a list of some of the most widely used zinc compounds:
Zinc halogenides (fluoride, bromide, chloride, iodide)
Sulfite, selenide, zinc arsenide
Thiocyanates, cyanides and thiosulfates
Hydroxo-zincates: amphoteric compounds formed from hydroxide and zinc oxide
Here is a list of some of the most interesting facts about zinc that are worth mentioning:
The 24th most common element that one can find on Earth’s crust is zinc
Zinc contributes to almost 0.0075% of the entire Earth’s crust
Zinc is also available in seawater, although it’s about 30 parts per billion
The first known use of zinc dates back to 1000 BC
The majority of the zinc (95%) are mined within ore deposits of sulfide
Zinc is the fourth most commonly used metal within the industry
Current zinc production includes 70:30; mining and recycling ration
In 1746, Marggraf defined the zinc atomic structure while proclaiming it has a distinct element
1. Briefly explain the zinc group elements.
The four constituting elements of Group 12 from the periodic table are collectively known as Zinc group elements. These include zinc (Zn), cadmium (Cd), mercury (Hg) and copernicium (Cn). Sharing the same group ensures that zinc, mercury and cadmium have almost similar chemical properties. In fact, all of them share the same silvery-white color along with very low melting and boiling points. Even mercury can be found in liquid state in normal room temperature whose boiling point is far lesser than any other metal. Further including, Group 12 contributes to come of the most toxic metals known to the periodic table. Their toxicity increases from zinc < cadmium < mercury.
2. What are the adverse effects of zinc in our environment?
As the production of zinc, and their mining keeps on increasing, the majority of the portion ends up at the surface. There are several adverse effects of excess zinc concentration. For starters, the untreated water from the industry contains large quantities of zinc, which in turn pollutes the water bodies. Zinc accumulated in the bodies of the fish leads to biomagnification (concentration of toxins at the lower level of the food chain leading to higher toxin levels at the upper levels). Similarly, firming lands are also being polluted from zinc. Zinc deposits in soil leads to a lesser chance of survival for the plants. Concentration of zinc more than 800 ppm can disrupt an entire ecosystem.