Chemistry Chapter 2 - Atomic Structure & Chemical Calculations

Chemistry Chapter 2 - Atomic Structure & Chemical Calculations

1. Dalton

   • All matter is made of atoms, and atoms are indestructible and cannot be broken down into pieces
   • All atoms of a particular element are identical to each other and different from the atoms of other elements
   • Atoms are rearranged in a chemical reaction
   • Compounds are formed when two or more different kinds of atoms join together

2. Atoms

   • Nucleus
     • In middle of atom
     • Contains protons & neutrons
     • Has positive (+ve) charge - due to presence of protons
     • Almost the whole mass of the atom is concentrated within the nucleus
     • Size is tiny compared to the atom as a whole
   • Electons
     • Orbit the nucleus
     • Negatively charged (-ve)
     • Tiny, but cover a lot of space
     • The volume of their orbits determines how big the atom is
     • Virtually no mass
     • They occupy shells around the nucleus