Module 2- Foundations in Chemistry

• Relative charges of subatomic particles:

  Proton: 1+

  Neutron: 0

  Electron: 1-
• Relative mass of subatomic particles:

  Proton: 1

  Neutron: 1

  Electron: 1/1836
• Location of subatomic particles:

  Proton: nucleus

  Neutron: nucleus

  Electrons: Orbitals
• isotopes: atoms of the same element with different numbers of neutrons (and therefore, different masses)
• electronegativity increases across a period:

  • the charge on the nucleus increases
  • the number of protons increases
  • increased attraction for outer electrons
  • bonding air are attracted more strongly
• electronegativity decreases down a group:

  • the bonding pair is held increasingly away from the nucleus
  • number of shells increases
  • distance of the outer electrons from nucleus increases
  • bonding pair of electrons is attracted less strongly