Mendeleev's first Periodic Table of Elements is shown here. (Image credit: ... The standard atomic weight of an element is the average mass of the element written in atomic mass units (amu).

The atomic mass of an element is the average mass of the different isotopes of the element. The atoms in the periodic table are arranged to show characteristics and relationships between atoms and ...

Can you name everything from Ac to Zr? Test your knowledge of the periodic table and see if you can top the leaderboard ...

The periodic table of chemical elements, often called the periodic table, organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic ...

Manvendra memorised each element’s name, atomic number, and atomic mass, accurate to two decimal places, and recited them ...

Looking at elements still within the periodic table, they could not find elements with high enough mass densities to explain what has been observed of asteroid 33 Polyhymnia, even if they were ...

In this periodic table of elements quiz, you have 10 minutes to name as many elements as you can, given only their symbol, atomic weight and the broad group they live in.