Atomic Structure

Atomic Structure

1. Subatomic Particles

   • Protons
     • Positive charge - +1
     • In the nucleus of an atom
     • # of protons changes with each element
   • Neutrons
     • Neutral subatomic particle
     • Inside the nucleus of an atom
     • Almost same mass as proton
     • Charged object doesn’t deflect path
   • Electrons
     • Negatively charged -> -1
     • found outside the nucleus

2. Atomic Number

   • The number of protons
   • EX) Hydrogen has 1 proton = atomic number 1

3. Mass Number

   • sum of protons and neutrons
   • EX) Aluminum has 13 protons, 14 neutrons = 27 mass number

4. Isotopes

   • Elements with the same atomic numbers but the number of neutrons vary
   • EX) Carbon has 6 protons, and can have 6,7, or 8 neutrons

5. Atoms

   • same number of protons/electrons

6. Ion

   • When the number of electrons and protons differ
   • Cation - more protons than electrons
   • Anion - less protons than electrons

7. Bohr's Model

   • Energy levels = amount of energies that electrons can have
   • Diagram Method 2 8 8 18 18 32 32
   • correct in assigning energy level to electrons
   • incorrect in assuming that electrons moved like planets in a solar system

8. Electron Cloud Model

   • Describes the POSSIBLE locations of electrons around the nucleus
   • Denser = more electrons

9. Atomic Orbitals

   • region around the nucleus where an electron is likely to be found.
   • can only contain 2 electrons at a time

10. Electron Configuration

    • Arrangement of electrons in their orbital
    • Most Stable = Low Energies (ground state)
    • higher energy = excited state