First 20 Elements Of The Periodic Table: The atomic number and symbols are important in chemistry. The atomic number of elements gives us an idea about the atomic structure of elements, such as how ...

For the first time those little numbers that appear beneath some of the commonest elements in the periodic table boxes are about to change from a single value to an interval of numbers An ...

This video is an interactive lesson in calculating an atom’s mass and atomic number. Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in shells. The numbers of ...

Note: This video is designed to help the teacher better understand the lesson and is NOT intended to be shown to students. It includes observations and conclusions that students are meant to make on ...

Ten elements that help make up the universe, including the carbon our biology is based on and the oxygen in the air we breathe, are now getting changed in an unprecedented way — they are getting their ...

One hundred fifty years after Russian chemist Dmitri Mendeleev published his system for neatly arranging the elements, the periodic table it gave birth to hangs in every chemistry classroom in the ...