Animated Solution for Chemistry - Periodicity in Properties: The atomic number of the element unnilennium is

Imagine you are a scientist who has just synthesized a brand new element in a particle accelerator. It exists for only a fraction of a second before decaying, but you have the data to prove it. What do you name it? Historically, the right to name an element belonged to its discoverer. However, during the Cold War, American and Soviet scientists frequently claimed discovery of the same superheavy elements simultaneously, leading to intense naming controversies known as the Transfermium Wars.

To resolve this chaos, the International Union of Pure and Applied Chemistry (IUPAC) stepped in. They established a systematic, temporary naming convention for any element with an atomic number $Z\ge 100$. This ensures that scientists worldwide have a standard way to refer to an element until its discovery is officially confirmed and a permanent name is agreed upon.

The IUPAC system is beautifully simple and highly logical. It relies on a set of numerical roots derived from Latin and Greek. To name an element, you simply take the roots corresponding to the three digits of its atomic number, string them together, and append the suffix -ium.

Here is the master key you need to remember: 0 = nil 1 = un 2 = bi 3 = tri 4 = quad 5 = pent 6 = hex 7 = sept 8 = oct 9 = enn

Let's apply this master key to the problem at hand. We are asked to find the atomic number for the element named unnilennium.

We can break this name down into its constituent roots:

1. un: Looking at our table, the root "un" corresponds to the digit 1. 2. nil: The root "nil" corresponds to the digit 0. 3. enn: The root "enn" corresponds to the digit 9.

Finally, the suffix -ium is added to denote that it is a metallic element, which is standard for all newly discovered superheavy elements.

When we string these digits together in order, we get 109.

Therefore, the atomic number of unnilennium is $Z=109$. This perfectly matches option (a).

To solidify our understanding, let's quickly reverse-engineer the names for the other atomic numbers given in the options:

Option (b) 102: The digits are 1 (un), 0 (nil), and 2 (bi). Combining these gives us unnilbiium. Option (c) 108: The digits are 1 (un), 0 (nil), and 8 (oct). Combining these gives us unniloctium. Option (d) 119: The digits are 1 (un), 1 (un), and 9 (enn). Combining these gives us ununennium*.

By mastering these ten simple roots, you unlock the ability to name any theoretical element in the universe. It is a perfect example of how chemistry uses systematic logic to bring order to the unknown.