Helium is the second-most common element in the cosmos, but it's far rarer on planet Earth. As part of our celebration of the periodic table's 150th birthday, reporter Geoff Brumfiel shares a ...

If you were to take every element in the periodic table and order them by how abundant they are in the Universe, you'd find something a little bit surprising. The most common element is hydrogen ...

We're pretty fortunate that our Sun wasn't among the very first stars in the Universe. Shortly after the Big Bang, the Universe was made exclusively of hydrogen and helium: 99.999999% of the ...

The periodic table traditionally taught in textbooks, which organizes elements based on chemical traits such as reactivity, places helium in the rightmost column with the other less reactive elements.

By the periodic table’s logic, all d-block elements should have filled s orbitals. But copper defies that logic. ... Most tables place helium atop the noble gases.

"If helium gets into the atmosphere, ... 2019 marks the 150th anniversary of the periodic table, which was originally conceived by Russian chemist Dmitri Mendeleev in 1869.

For one thing, the modern table has a bunch of elements that Mendeleev overlooked (and failed to leave room for), most notably the noble gases (such as helium, neon, argon). And the table is oriented ...

Since the invention of the periodic table 150 years ago this month, scientists have worked to fill in the rows of elements and make sense of their properties. But researchers have also pursued a ...