CHEM 1211K Lecture Notes - Lecture 1: Transition Metal, Unified Atomic Mass Unit, Avogadro Constant
Document Summary
In the late 1800s, henri becquerel and marie curie discovered that certain elements would constantly emit small, energetic particles and rays. Put something through it! use large target atoms use very small particle as bullet with very high energy. Bullet = alpha particles (positively charged), target atoms = gold foil. Atom mostly empty space because almost all the particles went straight through. Atom contains a dense particle that is small in volume compared to the atom but large in mass because of the few particles that bounced back. This dense particle is positively charged because of the large deflections of some of the particles. The atom contains a tiny dense center called the nucleus. Elements are made up of tiny particles called atoms. The nucleus has essentially the entire mass of the atom. The nucleus is positively charged, but also has a neutral component (protons and neutrons)
