1. Grade 9 Chemistry review
Atoms, Subatomic Particles, Diagrams …

2. Learning goals We are learning to calculate subatomic particles.
We are learning to draw Bohr and Lewis dot diagrams.
We are learning to calculate charges on ions.

3. The periodic table
ELEMENT: a pure substance that cannot be broken down.

4. organization

5. organization

6. organization Groups: The vertical columns of a periodic table.
These are elements with similar properties.
Identifies number of electrons in outer shell  valence electrons
Periods: The horizontal rows of a periodic table.
Identifies the number of shells in the atom

7. The groups Alkali Metals (Group I): Soft highly reactive metals.
Alkaline Earth Metals (Group II): light, reactive metals
Halogens (Group XVII): One of the most reactive groups on periodic table.
Noble / Inert Gases (Group XVIII): Very stable, rarely react with other chemicals.

8. The atom The smallest building block of matter.
Contains three sub-atomic particles:
Proton (p+): Positively charged, inside the nucleus.
Neutron (no): No charge, inside the nucleus.
Electron (e-): Negatively charged, in shells around the nucleus.
In neutral atoms, #protons = #electrons

9. Do you remember??? element name atomic number element symbol
atomic mass

10. Whoa!!! Atomic Number = Protons = Electrons
Neutrons = Atomic Mass – Protons
Isotope – same elements with different numbers of neutrons
thus have a different mass
C-12 and C-14 (number indicate the mass)

11. With your elbow partner
Find the element symbol, atomic mass, atomic number, protons, electrons, and neutrons for the following elements:
Magnesium
Hydrogen
Chlorine

12. Bohr diagrams Draw the nucleus
Write the number of protons and neutrons in the nucleus
Draw first ring (max 2 electrons in this ring)
Add electrons
Draw second ring (max 8 electrons in this ring)
Draw third ring if needed (max 8 electrons in this ring)

13. Your turn…
With your elbow partner, draw Bohr diagrams for the following:
Hydrogen
Carbon
Neon

14. Lewis diagrams Shows valence electrons only
Draw element symbol and add valence electrons starting at 12 o’clock
With your elbow partner, draw Lewis diagrams for following elements:
Nitrogen
Helium
Fluorine
Oxygen

15. ions
Atoms that have an unequal amount of protons and electrons are called ions.
Two types:
Cations (positive ions): # of electrons < # of protons
Anions (negative ions): # of electrons > # of protons
Metals form cations
Non-Metals form anions.

16. sodium Draw Sodium’s Bohr diagram Draw Sodium’s Bohr Ion diagram
Draw Neon’s Bohr diagram

17. fluorine Draw Fluorine’s Bohr diagram Draw Fluorine’s Bohr Ion diagram
Draw Neon’s Bohr diagram

18. Aluminum & Sulfur You try it with your elbow partner!!!
Draw Bohr diagram and Bohr Ion diagram

19. Naming ions Cations Anion Positive charge Sodium  sodium ion Na1+
Negative charge
Fluorine  fluoride
F1-

20. Learning goals We are learning to calculate subatomic particles.
We are learning to draw Bohr and Lewis dot diagrams.
We are learning to calculate charges on ions.

21. Please complete
P187 #1, 3, 4, 5, 7, 8
P191 #2, 4, 5, 6, 7, 8