Chemistry · Periodic Classification Of Properties · NEET
Follow three simple steps. Step 1: write the atomic number digit by digit. Step 2: replace each digit with its root word (nil=0, un=1, bi=2, tri=3, quad=4, pent=5, hex=6, sept=7, oct=8, enn=9) and join them in order. Step 3: add '-ium' at the end. Example: Z = 104 is 1-0-4, so un + nil + quad + ium = unnilquadium (symbol Unq). This matters for NEET because at least one question on element naming appears almost every year.
There are ten roots, one for each digit 0 to 9: nil (0), un (1), bi (2), tri (3), quad (4), pent (5), hex (6), sept (7), oct (8), enn (9). You spell the atomic number using these roots in the same order the digits appear. This is the single most tested fact of this topic, so learn the roots cold.
Take the FIRST letter of each root and capitalise only the first one. For Z = 105, the roots are un-nil-pent, so the symbol is Unp. For Z = 120, roots are un-bi-nil, symbol is Ubn. The symbol always has as many letters as the atomic number has digits (three letters for three-digit atomic numbers).
The '-ium' suffix is a fixed rule of the systematic (provisional) naming system, not a claim about the element's metallic character. Every provisional name of an element with Z > 100 ends in -ium, no matter what block it is in. So do not remove or change the ending.
The provisional name (like unnilunium for Z=101) is a temporary placeholder used until the element's discovery is confirmed and a permanent name is agreed. Once IUPAC ratifies the discovery, the discoverer suggests a permanent name (like mendelevium for Z=101) and a normal one- or two-letter symbol (Md). NEET loves to match provisional names with official names, so learn a few pairs.
Split the name into its roots and read each root as a digit. Example: 'ununennium' splits into un-un-enn-ium = 1-1-9 = atomic number 119. Reverse the process you use to build a name. This is exactly how NEET 2022 asked for Z=119.
Match the following IUPAC provisional names with their IUPAC official names. Column-I: (a) Unnilunium (b) Unniltrium (c) Unnilhexium (d) Unununnium. Column-II: (i) Mendelevium (ii) Lawrencium (iii) Seaborgium (iv) Darmstadtium. Which one of the following is correct?
The IUPAC name of an element with atomic number 119 is:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Yes. Direct questions asking the provisional name of a given atomic number (like Z=119 in NEET 2022) or matching provisional names with official names (NEET 2020) appear regularly, so this small topic gives easy marks.
118 is 1-1-8, so un-un-oct-ium = ununoctium, symbol Uuo. Its permanent name is oganesson (Og).
Memorize the roots first, as they let you build any provisional name. Then learn a handful of famous permanent-name pairs (101 mendelevium, 103 lawrencium, 106 seaborgium, 111 roentgenium) because matching-type questions use them.
When two labs claim the same new element (for example element 104 was called both Rutherfordium and Kurchatovium), IUPAC needs a neutral placeholder name based only on the atomic number until the real discoverer is confirmed. This avoids naming fights.
Yes. Roots repeat whenever a digit repeats. For 111 you get un-un-un = unununium (Uuu). Just read each root in order.
