[Chemistry Class Notes] on Bismuth Pdf for Exam

What is Bismuth?

Bismuth is a chemical element placed in group 15 and period 6 in the periodic table with the symbol Bi. The atomic number of bismuth is 83 with an atomic mass of 208.89. The electronic configuration of Bismuth is [Xe] 4f¹⁴5d¹⁰6s²6p³. Electronic configuration- 2,8,18,32,18,5. 

Bismuth has 5 electrons in its valence shell. Bismuth occurs as metal in nature itself but is more commonly found in ores of nickel, cobalt, tin, etc. When bismuth was discovered, scientists earlier mistook it for lead. Since its early days, it’s been used as an alloy. Alloys are mixtures of two or more elements combined together to form a mixture with the desired properties of its constituent elements.

Properties of Bismuth

Due to its long half-life, Bismuth is considered a fairly stable element. It is obtained from its ores and also as a by-product during the refining process of tin, copper, lead and from gold and silver ores.

Chemical Properties of Bismuth

Bismuth reacts with Oxygen at room temperature slowly to form its oxide Bi₂O₃ . Bismuth reacts with most acids. At higher temperatures, it burns to form its oxides. It has a commonly found isotope called Bismuth-209. Isotopes are elements with similar atomic number but different atomic mass and physical properties. Some radioactive isotopes are also known but none of them has any commercial applications.

Physical Properties of Bismuth

Bismuth exists in a solid-state at 20⁰C. It occurs as a brittle metal and is found in ores bismuthinite and bismite. It has a very low thermal conductivity. It is a highly dense material, looks silverish and has a pinkish hue. Among all metals, it is the most diamagnetic and has a very low thermal conductivity second to mercury. 

• Melting point – 520.5⁰F, 271.4⁰C, 554.6K

• Boiling Point – 2847⁰F, 1564⁰C, 1837K 

• Density – 9.79 g/cm³

• Atomic mass – 208.9

• Structure- Rhombohedral

• Bismuth expands when it solidifies which is different from usually what happens with other metals which contract on changing form, from liquid to solid

What is Bismuth Used for?

Bismuth is commonly used to make alloys to make it useful because of its brittle properties. It has very few commercial applications and only used in smaller quantities in preparation of chemicals and alloys. Bismuth is a relatively rare metal but is still available and has a good commercial value because of its multipurpose use. It is available in both commercial and higher quality grades. Some of the common uses of bismuth are:

Medicinal Uses

Colloids of bismuth are used as medicines. A common example is Bismuth subsalicylate which is used as a weak antacid. It is used in treating indigestion, discomforts in the stomach, diarrhoea, etc. Due to its antimicrobial properties, it is used as an active ingredient in some common ‘over the counter’ medicines like pink bismuth.

Cosmetics

It is commonly used as a pigment in cosmetics. Compounds of bismuth find uses in hair care products, cleansers, nail paints and fragrances. One of its compounds Bismuth oxychloride is used to give white colour in cosmetic products.

Industries

Bismuth is used as a catalyst in some of the chemical processes in the manufacturing of rubber and casting sharp objects. It’s used in X-rays and gamma detectors. It is also used as an electrocatalyst and in lubricants. It is used in fire alarms and sprinkler systems. Due to its low melting alloys, it also finds application in artistic purposes. Earlier, it was also used in typesetting. Blocks of letters were carved out by mixing bismuth in the mixture for increasing the clarity of the letters making them crisp and easy to read.

Alloys

It is used commonly to mix with metals with low melting points such as lead, cadmium or tin. Bismuth is also used as an alternative for lead. It is used to make Bend Metal, commonly used to make pipes that are supposed to be bent. It is mixed with cadmium in the ratio 60:40, for soldering purposes in electrical circuits and high power electrical devices.

Bismuth Uses in EverydayLife

The most common use of bismuth is as its compounds which are used as medicines. Eg. bismuth subsalicylate as a weak antacid is used to cure stomach problems. It has a high melting point, so it is mixed with iron or lead to make them withstand different weathers and be more durable. It is also used in safety systems such as sprinkler systems and fire alarm systems.