Chemistry

Chemistry

1. What is an atom?

   • The smallest particle of a chemical element that can exist

2. What is an element?

   • A pure substance made of only one type of atom

3. What are the subatomic particles in an atom?

   • Protons
     • Positive charge
   • Neutrons
     • Neutral charge
   • Electrons
     • Negative charge

4. Electron arrangement

   • First shell = Up to 2 electrons
   • Second & Third shell = Up to 8 electrons

5. Periodic Table

   • Atomic number = Number of protons/electrons
     • Atomic mass = mass of protons + neutrons
   • Alkali Metals- Group 1 Very reactive with water, one valence electron, Largest atomic, Low melting and boiling points
     • Alkaline Earth metals- Group 2 valence of 2 electrons Readily lose electrons
       • Halogens- Group 17 brightly coloured, 7 electrons in outer shell, valence of -1 electron,, non-metals, highly reactive

6. Isotope:: Have a different number of neurons than protons

   • Ion: a charged atom