Metallic Hg ( Mercury )

Understanding

In chemistry, a metal (Greek: Metallon) is a chemical element that is ready to form ions (cations) and has metallic bonds, and sometimes it is said that he is similar to the cation in a cloud of electrons. Metal is one of three groups of elements as distinguished by ionization and bonding properties, along with the metalloids and non-metallic. In the periodic table, a diagonal line drawn from boron (B) to polonium (Po) distinguishes metals from non-metallic. Element in this line are metalloids, sometimes called semi-metal element in the lower left are metals; elements to the right above is a non-metallic. More non-metallic in nature rather than metal, but there are a lot of metal in the periodic table. Some famous adalahaluminium metal, copper, gold, iron, tin, silver, titanium, uranium, and zinc. Allotropes of metals tend to be shiny, soft, and a good conductor, while non-metals are usually brittle (for solid non-metallic), not shiny, and insulators.

Physical properties

Metals generally have high numbers in the electrical conductivity, thermal conductivity, luster and density properties. Metals that have a density, hardness, and low melting point (for example, alkali metals and alkaline earth metals) are usually very reactive. High number of free electrons in all forms of solid metal causes the metal never looked transparent.

The majority of metals have a higher density than the non-metallic. Even so, variations in the density of this difference is very large, ranging from metallic lithium as the density of the smallest to the osmium to the metal with the greatest density.

Chemical properties

Metals tend to form cations by removing electrons, then reacts with oxygen in air to form alkaline oxides. For example:

4 Na + O2 → 2 Na2O (Sodium Oxide)

Ca 2 + O 2 → 2 CaO (Calcium Oxide)

4 Al + 3 O2 → 2 Al2O3 (Aluminum Oxide)

Transition metals such as iron, copper, zinc, and nickel, takes much longer to oxidize. Others, like palladium, platinum and gold, did not react with air at all. Some metals such as aluminum, magnesium, some kinds of steel, and titanium have some sort of "protector" on the very outside, so the buffer is not accessible by oxygen molecules. The process of painting, anodizing or plating on the metal is usually the best measures to prevent corrosion.

Metal hazard Hg

Mercury is highly toxic, causing damage to the nervous system at even relatively low levels of exposure. This is especially harmful to the development of children unborn.It collects in the human body and animals and can be concentrated through the food chain, especially in some types of fish. Commission of the Directorate General for Health and Consumer Protection recommends that women who are breastfeeding or are pregnant or maybe they should limit their consumption of large predatory fish such as swordfish, shark, marlin, pike and tuna.

It is known that mercury has no respect for national or regional borders, long-distance travel by air, and has contaminated both European and global food supplies at levels that are significant risks to human health, according to the World Health Organisation, food safety authorities, health and public health professionals around the world. Even the arctic, which has no sources of mercury pollution, have dangerous levels of contamination in marine mammals and other species that are part of the food supply.

The chemistry of mercury in the environment and form.

Mercury enters the environment (air, water and soil) mainly through:

* Coal combustion.

* Municipal and medical waste incinerators.

* Steel production.

* Cement production.

* Chlor-alkali production

* Crematoria

* Artisanal gold mining

* Dental amalgams

* Mercury-containing waste

* Consolidation and repair of metal ores

Mercury Exposure and effect

Mercury compounds are highly toxic to humans, ecosystems and wildlife. High doses can cause death in humans, but also relatively low doses can have serious impact. Adverse neurodevelopmental, and recently linked with possible harmful effects on the cardiovascular, reproductive and immune systems.