An element's atomic number defines it. An element with 17 protons will always be chlorine. However an element's mass numbers can vary, which means that it can have different numbers of neutrons. So ...

Snapshots of the hydrogen jet Shadowgraphs at the time of impact of the high-intensity laser pulse on the jet of hydrogen. A weaker light pulse sent in advance ...

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 ...