Trends on the Periodic Table: Students learn to describe the pattern in atomic number, atomic mass, atomic radius, ionization energy, and electron affinity as they look across a period and down a ...

Electron affinity, defined as the energy released when an electron attaches to a neutral atom, is a fundamental parameter in understanding atomic reactivity and material properties. Negative ion ...

The electron cloud has a radius 10,000 times greater than the nucleus, according to the Los Alamos National Laboratory. Protons and neutrons have approximately the same mass.