The atomic number of Unnilunium is _______.

Solution

Chemistry ma’am · 3 steps

Break the name into its number roots and read them as digits, left to right.

1. IUPAC number roots. Temporary IUPAC names are built from roots for digits: nil = 0, un = 1, bi = 2, tri = 3, quad = 4, pent = 5, hex = 6, sept = 7, oct = 8, enn = 9. The ending -ium is added at the end.

   Part of the name	Digit
   un	1
   nil	0
   un + ium	1

2. Read the digits. Un-nil-un-ium gives the digits 1, 0, 1 in that order. This is element 101, mendelevium (Md), an actinide.
3. So. The atomic number of Unnilunium is 101.

The common slip: 110. Mixing it up with Ununnilium (un-un-nil) gives 110. Here the order is un-nil-un, so the digits are 1, 0, 1.

The idea to keep. For any IUPAC temporary name, split it into digit roots (nil 0, un 1, bi 2, tri 3 and so on) and write the digits in the same order they appear. The -ium ending carries no number.

Answer from the NTA final answer key. Solution by PrepWiser.