أكاديميا - كولنز - معاجم الجيب العلمية - الكيمياء - انكليزي - فرنسي - عربي الحرف ٢_ g

Academia - Collins - Pocket Scientific Dictionaries - Chemistry - English - French - Arabic Letter 2_ G


glycol glycol m

Glycol. This substance consists of 1,2-ethane-diol and is used as an antifreeze.
The compound contains two alcohol groups (OH), and is made from ethene by oxidizing it to epoxytane, then adding water to give the diol. Etene is obtained by cracking petroleum.

Ethane - 1, 2 diol
Epoxytane
Etienne


gold
or m

Gold is a precious metal, and it is so because it is used in
Jewelry is often used as a substitute for money. It exists freely in nature, not combined with other elements, and its main reservoirs are found in South Africa and the Soviet Union.

Gold is “chemically very inert and only reacts with strong oxidizing agents such as chlorine and certain acids such as aqua regia.” It is a soft metal and is mixed in most of its uses with copper or silver. The pure gold standard is 24 karat. As for 9 karat gold, it means that it contains 9 parts gold and fifteen parts copper, i.e. 37.5% gold. This is a harsh mixture commonly used in jewelry.


gram (g)
gramme m

Gram (g). The unit of mass, mass, is equal to 1/1000 of a kilogram and is used in all scientific works. Its symbol is (g), such as 100 g.


graphite
graphite m

Graphite. A heterogeneous form of carbon found in nature as a plumbago. Charcoal consists of small particles of graphite. It is a giant structure in which carbon atoms are connected to each other in a hexagonal arrangement in layers or surfaces.

Carbon atoms in hexagonal surfaces.
Strong links.
Weak links.
Sliding surfaces.

There are strong bonds between atoms on surfaces, but weak bonds between different surfaces. Surfaces can slide over each other. As a result of this property, graphite is very useful as a lubricant, and of course in pencils, where the pencil leaves layers of graphite on the paper.

Graphite is also used as a pathway in extracting elements such as sodium, aluminum and chlorine due to it being an electrical conductor.


group
group m

A group in which the elements in the table are horizontal periods arranged in periodic tables and vertical groups. The elements in these groups have similar chemical properties, such as:

Group | Lithium, sodium, potassium
Group || Beryllium, magnesium, calcium
Group ||| Boron, aluminum
Group IV carbon, silicon
Group V nitrogen, phosphorus
Group VI oxygen, sulfur
Group VII Fluorine, chlorine, bromine
Group 0 Helium, neon, argon

Each of these groups has a distinct electronic configuration, meaning that the outer electronic shell contains the same number of electrons for each of the group members. Moreover, this number is the same as the group number.