1. The Atom Contains 3 subatomic particles: The dense center (nucleus) of the atom contains: Neutron - a particle with no charge. Proton - a particle with a positive charge. Electrons are tiny particles that move around the nucleus. - negative electrical charge. - same # of positive and negative charges = neutral.

2. The Bohr Model

3. Explain and draw a Bohr model of an atom. Understand the movement of electrons when energized. Understand and perform a Flame Test Compare and contrast positive and negative ions. Key Words OrbitPlanetary model Flame Test

4. hypothesized electrons occupy precise positions. specific distances around the nucleus called orbits or shells. only a specific number of electrons can occupy each orbit. called the “planetary model” Bohr (1913)

5. 1 st – holds two electrons (e - ) 2 nd – holds eight e - 3 rd – holds eight e - Ever element has a different number of electrons. Electrons occupy the closest orbital first.

7. ColourElement greencopper yellowsodium redstrontium yellow-greenbarium orange-redcalcium purplepotassium purple-redlithium Elements give off a unique colour of light when heated - used to detect the presence of a metal This is known as a flame test. Bohr model explains the colours as “jumps” electrons make when energy is added.

8. Electrons are always moving - have energy. Given more energy (heat, light, electricity) electrons will jump up to a new further orbit. When electrons drop back down to previous orbit they release the energy as light. Elements have different number of electrons – different “jumps” – different spectrum of colour.

9. Energy level 1 Energy level 2 Energy level 3 Energy level 4 Ground State

10. Isotopes: Atoms of the same element with the same number of protons but a missing or extra neutron. helium helium isotopes The nucleus of some isotopes are unstable and break apart over time - radioactivity.

11. The Atom Contains 3 subatomic particles: Neutron – nucleus particle with no charge. - can vary within an element - ISOTOPES. Proton – nucleus particle with a positive charge. Electrons – negative particles move in specific orbits. - e - jump/drop orbits releasing energy. - same # of positive and negative charges = neutral.

12. How many electrons are able to occupy: the first orbit? the second orbit? the third orbit? Draw a Bohr model of the atom carbon which has six electrons. Draw a Bohr model of the atom aluminum which has 13 electrons.