How can the periodic table be used to predict new elements?

1 Answer

The Periodic Table can predict the properties of new elements, because it organizes the elements according to their atomic numbers.


However, creating new elements is not a simple process.

Scientists use particle accelerators to smash light atoms into a thin metallic foil that contains heavier atoms.

They hope that the two nuclei at the centre of these atoms will fuse and form a heavier nucleus.

When these heavy elements form, they are usually highly unstable.

The new elements decay so quickly that we don’t usually see the element itself.

Instead, we see a decay product.

In that respect, even new elements aren't always "discovered" directly.

In some cases, scientists haven’t synthesized enough of the element for us to know what the element even looks like!

Nevertheless, we consider the elements as known.

We name them and list them the periodic table.

For example, in 2003, scientists first observed element 115 (ununpentium, #"Uup"#).

They bombarded americium-243 with calcium-48 ions and produced four atoms of #"Uup"#, which lived for less than one fifth of a second.

#""_20^48"Ca" + _95^243"Am" → _115^288"Uup" + 3 _0^1n#

It took until September 2013 for the discovery to be confirmed, and about 50 atoms have been synthesized to date.

We can predict the properties of #"Uup"# because the Periodic Table organizes elements according to their atomic number.


#"Uup"# appears below bismuth in Group 15 of the Periodic Table. Its outermost electron configuration is #7s^2 7p^3#.

#"P, As"#, and #"Sb"# all form compounds with oxidation states of +5 and +3.

#"Bi"# tends to form only +3 compounds because of a phenomenon called the “inert pair effect”.

We predict that #"Uup"# will continue this trend and form only +3 and +1 oxidation states.

Nitrogen(I) and bismuth(I) are known but rare, but ununpentium(I) may be more stable.

Element 114 (flerovium) appears to have noble gas-like properties. If this is the case, ununpentium will likely form +1 cations, since #"Uup"^+# will have the same electron configuration as flerovium.