Chemistry

• What is an element 


  A substance which contains only 1 type of atom.
• Air is a _______

  Mixture.
• What is a compound?


  A compound is a substance where 2 or more different elements are chemically bonded together (with a fixed ratio).
• Explain why an unbalanced chemical equation cannot correctly represent a reaction.

  The numbers of the atom must be the same before and after the reaction.
• What is an isotope?


  Atoms with the same number of protons but a different number of neutrons.
• What are the relative masses for both a proton and a neutron?

  Proton = 1

  neutron = 1
• What is the mass number.

  The number of protons + neutrons.
• Explain why ionic compounds are usually solid at room temperature.


  They have strong electrostatic forces which require a lot of force to break apart.