Atomic Structure

Atomic Structure

1. What the atom looks like

   • Atom is a combination of electrons, protons and neutrons
   • Has a nucleus (made up of protons and neutrons), surrounded by shells filled with electrons
     • (Modern model "electron cloud")
       • Previous models throughout history had differing theories- ex. plum pudding model (idea that atoms were a bunch of electrons surrounded by a mass of positive charge)

2. Properties

   • Protons: positively charged particles (found in the nucleus)
   • Neutrons: particles with no electrical charge- but has the same mass as a proton (also found in the nucleus)
   • Electrons: negatively charged particles that are found in electron shells outside the nucleus

3. Behaviour

   • The number of electrons in an atom's outer shell determine its behaviour
     • Differing amounts of electrons determines what element the atom is
   • The more electron shells in an atom, the more unstable it becomes- as there is more distance between the nucleus and the outer shell
     • Bigger distance = weaker attraction

4. Why bonding happens

   • Atoms bond with one another to try and become more stable.
   • There are three types of bonding: Ionic, metallic and covalent
     • Ionic: bonding between + metal ion and - non-metal ion
       • Metallic: between two metal ions
         • Covalent: between two non-metal ions
   • When two atoms bond together, they share electrons between their outer shells, simultaneously filling the outer shells of both atoms- which makes both more stable