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Some of the elements in the periodic table with atomic numbers greater than 100 had dual symbols and names which created confusion. Thus, IUPAC decided to make a commission on the nomenclature of inorganic chemistry to eliminate the confusion of identifying the elements and assign a clear system of nomenclature. The elements with atomic numbers above 100 have two lettered symbols which are accepted by the IUPAC. As the elements below the atomic number 104, having two lettered symbols tends to duplicate, the IUPAC suggested using three-lettered symbols for elements of atomic number 100 or above it.
Key Terms: Nomenclature, elements, atomic number, IUPAC, numerical roots, symbols, periodic table
Elements with Atomic Number Above 100: Process of Naming
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The IUPAC eradicated the naming process of the elements which created confusion and recommended methodical naming of the elements. The rules by the commission which needed to be followed were:
- Shortening of the names assigned to the elements
- The atomic number and the element should be directly or indirectly interrelated.
- The name of the element must end with "ium” irrespective of the element being metallic, non-metallic, or having an atomic number greater than 100.
- The assigned symbol of the element should contain three letters
- The symbol of the element should be related to the name and the atomic number
Nomenclature of Elements with Atomic Number Above 100
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| Digit | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
|---|---|---|---|---|---|---|---|---|---|---|
| Root | Nil | un | Bi | Tri | Quad | Pent | Hex | Sept | Oct | enn |
| Abbreviation | n | u | b | t | q | p | h | s | o | e |
- Numerical roots of the required number from 0-9 can help in deriving the names from the atomic number
- The atomic roots are arranged according to the digits which eventually forms the atomic number with the ending of “ium” to be spelled
- Each root in the element is pronounced separately
Elements with Atomic Number Above 100
IUPAC Nomenclature
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IUPAC nomenclature has been specified below:
| Atomic number | Name | Symbol | IUPAC name | IUPAC symbol |
|---|---|---|---|---|
| 101 | Unnilunium | Unu | Mendelevium | Md |
| 102 | Unnibium | Unb | Nobelium | No |
| 103 | Unniltrium | Unt | Lawrencium | Lr |
| 104 | Unnilquadium | Unq | Rutherfordium | Rf |
| 105 | Unnilpentium | Unp | Dubnium | Db |
| 106 | Unnilhexium | Unh | Seaborgium | Sg |
| 107 | Unnilseptium | Uns | Bohrium | Bh |
| 108 | Unniloctium | Uno | Hassinium | Hs |
| 109 | Unnilenium | Une | Meitnerium | Mt |
| 110 | Ununnilium | Uun | Darmstadtium | Ds |
| 111 | Unununnium | Uuu | Roentgenium | Rg |
| 112 | Ununbium | Uub | Copernicium | Cp |
| 113 | Ununtrium | Uut | ||
| 114 | Ununquadium | Uuq | ||
| 115 | Ununpentium | Uup | ||
| 116 | Ununhexium | Uuh | ||
| 117 | Ununseptium | Uus | ||
| 118 | Ununoctium | Uuo |
Things to Remember
- There are 118 elements in the periodic table out of which 24 elements are manmade.
- The elements having an atomic number of more than 100 are also known as superheavy elements
- The element with atomic number 900 is named Enilnilium with the symbol Enn
- Element 119 have the name Ununennium(Uue) is also known as eka-francium
- In a periodic table, the electronegativity increases across a period from left to right whereas it decreases down a group.
- The tendency of an element to lose electrons is known as ionization enthalpy
- Isoelectronic species are the atoms and electrons which contain an equal number of electrons
- The removing of an electron from an atom leads to the formation of cation whereas gaining of an electron leads to the formation of anion
Sample questions
Ques. What is the IUPAC symbol and name for the element with atomic number 120? (2 Marks)
Ans: the numeric root for 1 is un, 2 is bi, and 0 is nil. Thus the symbol is Ubn and the name is Unbinilium.
Ques. Show the presence of the 18 elements in the 5th table of the periodic table. (2 Marks)
Ans: 5s<4d<5p is the order in which the energy of the available orbitals, 4d,5s and 5p increase when n=5, l=0,1,2,3. There are a total of 9 orbitals available. A maximum of 18 electrons can be accommodated which is why there are 18 elements in the 5 table.
Ques. Arrange Si, Be, Mg, Na, P in increasing order of their metallic character with relevance to the atomic number and the position in the periodic table. (2 Marks)
Ans: metallic character decreases across a group from left to right whereas it increases down a group from top to bottom. Thus, the order of increasing metallic character is: P<Si<Be<Mg<Na
Ques. Find out the element with the largest and the smallest size among Mg, Al, Mg2+, Al3+ (2 Marks)
Ans: there is a decrease in the atomic radii across a period. Cations are smaller in shape when compared to their parent atoms. Among isoelectronic species, such an element will have a smaller radius and have larger positive nuclear charge. Thus the smallest element is Al3+ and the largest is Mg.
Ques. Among P, S, CI, F, which element have the least negative electron gain enthalpy and the most negative electron gain enthalpy? (3 Marks)
Ans: the negativity of the electron gain enthalpy increases from left to right across the periodic table. Whereas, the negativity of the electron gain enthalpy becomes less which moves from top to bottom down the table. The repulsion is greater when an electron is added to the 2p-orbital than to the 3p-orbital. Thus the element which has the least negative electron gain enthalpy is phosphorus and the element which has the most negative electron gain enthalpy is chlorine.
Ques. Write the chemical reaction with water that shows the Na2O as a basic oxide and Cl2O7 as an acidic oxide. (5 Marks)
Ans: Cl2O7 with water forms a strong acid whereas Na2O with water forms a strong base.
Cl2O7 + H2O 2HCIO4
Na2O + H2O 2NaOH
Litmus paper helps in the qualitative testing of the basic and acidic nature of the solution.
Ques. Give the formula of the compound which is formed by silicon and bromine (3 Marks)
Ans: the formula of the compound formed by the combination of silicon and bromine is SiBr4.
Silicon is an element that belongs to group 14 of the periodic table. It has a valency of 4. Bromine belongs to the halogen family and has a valency of 1.
Ques. Give the formula of the compound which is formed by aluminum and sulfur (3 Marks)
Ans: The compound which is formed by aluminum and sulfur is Al2S3.
Aluminum belongs to group 13 of the periodic table with a valency of 3. Sulfur has a valency of 2 and belongs to group 16.
Ques. What is the process of naming an element of the atomic number above 100? (3 Marks)
Ans: A three-lettered temporary name is initially assigned to the new element. Later the voting of IUPAC representatives from each country determines the permanent name of the element. The permanent name is supposed to pay tribute to the respective scientist or the country. Although elements up to atomic number 118 have been discovered, the naming of elements with atomic number 113, 115, 117, and 118 are yet to be done.
Ques. What are the different types of elements based on the type of atomic orbitals filled with electrons? (2 Marks)
Ans: the elements in the column of the periodic table show similar chemical behavior as they have the same distribution of electrons in the outermost orbitals. Depending on the type of atomic orbitals filled with electrons, the elements are divided into four blocks: p- block, s-block, f-block, and d-block.
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