Gold

Gold is a precious metallic element with atomic number 79 and is a part of the periodic table. Gold falls under the sixth period and the group eleven in the periodic table. Gold is a transition metal. The IUPAC defines a transition metal as an element which has a partly filled subshell, or an atom which may give rise to cations despite having an incomplete subshell. 

Occurrence

Gold is a naturally occurring element. It is widespread in all igneous rocks, at low concentrations. It is estimated that its abundance in Earth's crust is about 0.005 part per million. It occurs mainly in the natural state. It is usually chemically pure, except with tellurium, selenium, and bismuth. The only isotope that occurs naturally for this element is Au-197.

Gold also appears in association with deposits of copper and lead, and while the quantity present is sometimes exceedingly small, it is readily extracted as a by-product in the processing of these base metals. It is highly unusual to see large masses of gold-bearing rock rich enough to be called ores.

Two types of deposits contain a substantial amount of gold. First, the hydrothermal veins, where gold is associated with quartz and pyrite (fool's gold) and second, the deposits, which are mainly derived from the weathering of gold-bearing rocks 

Chemical Symbol of Gold

The chemical symbol of gold is Au. This symbol is taken from the first two letters of the Latin name of gold: Aurum. 

Gold Atomic Number

The atomic number basically determines the number of protons in the particular element. An element is identified by the number of protons, which is given by the atomic number. 

The atomic number of the element Gold is 79. 

Gold Electron Configuration

Image will be added soon

An atom has various shells on which electrons revolve around the nucleus. The number of electrons present in each of the shells is known as the electronic configuration of an element.

The electronic configuration of Gold is [Xe] 4f145d106s1.  In a simpler form, the electrons per shell of the Gold atom can be written as [2, 8, 18, 32, 18, 1]. Gold can have a valency between (-1) and +5, the most common being +1 and +3.

Atomic Mass of Gold

The atomic mass of an element refers to the mass of one atom of that element, which is measured in atomic mass units (u), where one atomic mass unit is equivalent to 1/12 the mass of carbon-12 isotope. When calculating the atomic mass of a particular element, we add up the mass of the protons and neutrons, because the mass of the electrons is negligible compared to their mass. 

The average atomic mass for Einsteinium is 196.97. It varies depending on the isotope.  

Isotopes of Gold

Isotopes are forms of an element with the same atomic numbers but different mass numbers, i.e. a different number of neutrons. Gold (Au79) has a single stable isotope, Au-197, and 36 radioisotopes, with Au-195 being the most stable with a half-life of 186 days. Gold is now known to be the heaviest mono-isotopic metal element.  

Properties of Gold

Group

11

Melting point

1064.18°C, 1947.52°F, 1337.33 K

Period

6

Boiling point

2836°C, 5137°F, 3109 K

Block

d

Density

19.3 g/cm3)

Atomic number

79

Relative atomic mass

196.967

State at 20°C

Solid

Key isotopes

Au-197

Electron configuration

[Xe] 4f145d106s1

CAS number

7440-57-5

Physical Properties of Gold

  • Gold is an amazing thermal and electrical conductor. 

  • The element is highly resistant to corrosion and is exceptionally durable. It is not harmed by air and most of the reagents

  • Gold is lustrous. It is also malleable and ductile. 

  • Gold in its purest form is extremely soft. In order to bestow strength to it, it is alloyed with another metal.

  • Gold appears in a slightly reddish yellow colour when available in bulk. But when finely separated, it becomes black, violet, or ruby.

Chemical Properties of Gold

  • The most common gold compounds are chloro-auric acid and auric chloride.

  • Gold is insoluble in most acids but can be dissolved in Aqua Regia (Royal Water). Aqua Regia is a mixture of hydrochloric acid and nitric acid, in which gold forms a tetrachlorocuprate anion. It also dissolves in alkaline solutions cyanide. 

  • Gold is one of the least reactive metals, according to the reactivity series of metals. It comes just before platinum, the most non-reactive metal.  

Uses of Gold

  • Gold is mainly used for the manufacture of jewellery, glass and various parts in electronics. Around 75% of the world's jewellery is made using gold. 

  • Gold may be rendered into a thread and used for embroidery. 

  • A thin film of this metal is placed on the windows of a large building to simulate the heat of the light. 

  • Gold is also used in medicinal products. Its radioactive isotope Au-198 is used to treat tumours in the body.

  • A thin layer of gold is applied to astronaut helmets to protect them from UV radiation.

FAQ (Frequently Asked Questions)

1. Why is Gold Used to Make Jewellery and for Embroidery?

Gold is a lustrous metal and has a bright sheen. It is malleable, pliable, and ductile, which allows jewellery designers to mould it into intricate designs. It looks beautiful when worn and has traditionally been used as an adornment. Since gold is highly ductile, it can be made into a fine thread which can then be used for decorative embroidery.

2. Does Gold Have Any Applications in the Space Exploration Sector?

Gold does play a pivotal role in the space industry as a thin coating of gold is done on the helmets of the astronauts to protect them from radiation during their time in space.