The Periodic Table

The Periodic Table

1. Mass no.

   • The no. of protons + the no. of neutrons

2. The atom

   • The smallest unit that can take part in an ordinary chemical reaction

3. Proton no.

   • The no. of protons which is equal to the no. of electrons in a neutral atom.

4. Core electrons

   • Electrons found in the energy shell closest to the nucleus.

5. Valence electrons

   • Electrons found in the outermost energy shell of an atom

6. Alkali Metals (Group 1)

   • Soft
   • Conduct electricity
     • Free electrons to carry charge
   • Reactivity increases DOWN the group
     • Atomic radius is increasing, electron has to travel further to reach nucleus
   • Melting and boiling point increase up the group
     • Atomic radius increasing ,weaker bonds between electron shells