1. The Periodic Table and Atomic Structure
Section 2.1

2. Review
Four classical atomic models
Quantum Mechanical Model

3. Objectives
Distinguish between metals, non-metals, and metalloids in terms of distinguishing properties
Explain the structure of the periodic table
Identify important families and elements
Describe atomic theory in terms of subatomic particles and location (nucleus, energy levels)
Define atomic number, mass number, isotope, and atomic molar mass and be able to identify these for a given element
Determine numbers of protons, neutrons and electrons for a given element
Describe the process of ionization and formation of cations and anions
Identify patterns in the periodic table for valence electrons and energy levels
Relate ionization to the octet rule

4. Law of Conservation of Mass
Antoine Lavoisier
Mass is neither created or destroyed
The total mass of the reactants equals the total mass of the products

5. The Elements 115: basic building blocks
90 naturally occurring, 25 synthetic
Split into 3 classes
Metals
Non-metals
Metalloids

6. Metals Most elements (75%) Silver/grey and shiny
Conductors of heat and electricity
Malleable and ductile
Most solid at room temperature
Reactivity varies
Most reactive is francium (left and down)
Inert= unreactive

7. Non-Metals 17 elements Grouped based on their different from metals
Vary is state, color and reactivity
Highly reactive= fluorine (right and up
Inert= noble gases
About half will appear at molecules (more than one atom)

8. Metalloids Remaining elements
Properties intermediate between metals and non-metals
Along the staircase (except aluminium)
Ex. Silicon, arsenic, boron

9. The Periodic Table

10. The Periodic Table Organizes elements based on chemical properties
Metals on left side and centre
Non-metals on far right
Exception hydrogen (learn more later)
Metalloids between two
Shows name and symbol for element
Get to know the symbols!

11. The Element Game
For the following, identify as being a metal, non-metal or metalloid
Hydrogen
Sulfur
Calcium
Tin
Gold
Boron
Aluminum
Xenon

12. Pre-test For the following, give the element’s name or symbol: Calcium
Hydrogen
Sulfur
Phosphorus Mg Na

13. Important Families/ Groups
Vertical columns
Groups of elements with similar chemical/physical properties
Group 1: alkali metals
Soft, shiny, silver, very reactive with water
Compounds white and soluble in water
Group 2: alkali earth metals
Shiny, silver
White compounds but not as soluble

14. Important Families cont…
Group 17: halogens
Non-metals
Very reactive
React with alkali metals to make salts
Group 18: noble gases
Very unreactive

15. Periods
Horizontal rows
Have the same number of levels of electrons

16. To Do
Crossword
What’s in a Name?
ELEMENTary My Dear Watson

17. Atomic Theory Atoms are very small (10-10 m in diameter)
What are three kinds of subatomic particles?
Protons, Neutrons and Electrons
Where are they found?
Protons and Neutrons- inside the nucleus
Electrons- outside the nucleus
Protons and neutrons are over 99.9% of total mass
Imagine this: our classroom filled with iron. If we take out the nuclei for all the iron atoms and place them side by side, they would be as big as a period in a book. But that period would almost equal the mass of the room full of iron

18. Protons Has a positive charge (p+) Mass of 1.67x10-27 kg
The number of protons defines the element and is called the atomic number
All helium atoms have a 2 p+ and every atom with 2 p+ is helium

19. Neutrons No charge (n0) Mass of 1.67x10-27 kg
The number of protons and neutrons together make the atomic mass of the atom
If an atom has 8 protons and 10 neutrons, its atomic mass is 18
If an element has an atomic number of 24 (protons) and an atomic mass of 52 (protons and neutrons) it has 28 neutrons

20. Electrons Charge of 1- (e-1) Mass of 9.11x10-31kg
Electrons are so small that they are not factored into the atomic mass
In an atom the number of protons = the number of electrons

21. Atomic Number Number of protons Determines the element
Can you find the atomic number of the following elements? Pb Hg
tin
chlorine
platinum Cu
manganese
lithium
As we move through the periodic table, what do you notice about the ordering of atomic numbers?

22. Mass Number and Isotopes
Isotope- atoms of same element with different number of neutrons
Ex. Common form of hydrogen has one proton and no neutrons. 1/ hydrogen atoms have a neutron, called deuterium (“heavy” hydrogen)
Each isotope given a mass number
Equals total number of protons and neutrons (don’t include electrons- too small)
# of neutrons= mass number – atomic number

23. Mass Number and Isotopes cont…
Can be shown as:
Mass number
element symbol
atomic number
Ex. Oxygen-16
What would be the symbols for oxygen-17? Oxygen- 18?

24. Mass number and isotopes
Name:
#p = _____
#n = _____
#e = _____
Name:
#p = _____
#n = _____
#e = _____

25. Practice: Fill in the chart!
Element Name
Mass Number
Number of Protons
Number of Neutrons
calcium 41
uranium
238
aluminum 14 9 5 20 10
iron 30

26. Atomic Molar Mass Shown in the periodic table
Average mass of element’s isotopes
Number of electrons equals number of protons (in neutral atoms)
Atomic molar mass

27. Bohr Model of the Atom
Neils Bohr- proposed that electrons moved around a nucleus at a specific fixed distance
Energy level
Electrons could move up levels by absorbing energy
Electrons could move down levels by losing energy
BUT each energy level can only have a certain maximum number of electrons

28. Energy Levels Electrons occupy energy levels
Region around nucleus either empty or contain electrons
Increase energy when get further from the nucleus
Specific number of electrons/level
First level- 2 electrons
Next levels- 8 electrons
Energy level can be empty, partly or completely filled

29. Drawing Atoms Drawings include: Ex. Hydrogen Lithium Sodium Oxygen
Number of protons (in nucleus)
Number of neutrons (in nucleus)
Electrons in correct energy levels (how many electrons can be in each level?)
Ex.
Hydrogen
Lithium
Sodium
Oxygen
Sulfur
Helium
Neon
Argon
Calcium

30. Valence Electrons Electrons in the outermost energy level
Valence number- number of electrons an element can lose/gain to combine with other elements
How many valence electrons do each of the following elements have?
Oxygen?
Magnesium?
Chlorine?
Argon?
Carbon-14?

31. The Octet Rule For understanding how atoms bond
Atoms want to have eight electrons in their valence shell (which shell is this?)
More stable when have full energy levels
What are these elements like with full energy levels?
Noble gases!
Gain/lose electrons to be like their closest noble gas
Ex. Chlorine will gain one electron to be like argon
Exception: hydrogen, lithium and beryllium. Why? Who do they want to be like?

32. What Now?
When we gain/lose electrons from an atom, what happens to its charge?
Ex. Fluorine gains one electron to fill its outer octet. What is its electrical charge now?
Gaining/losing electrons process called ionization
Results in positively charged or negatively charged ions

33. Formation of Ions
Elements can lose or gain outermost (valence) electrons
Called ionization
Makes ions (positively or negatively charged)
Allows metals and non-metals to form compounds
eature=related

34. Cations Positively charged ions Metal ion loses electrons
Where do the electrons go?
To another atom
Why would the atom be positively charged if it loses electrons?
Ex Magnesium
Loses 2 electrons
What would the diagram look like before? After ionization?
Put charge as a superscript: ex. Mg2+

35. Anions Negatively charged ions Non-metal gains electrons
Where do the electrons come from?
From atoms that lose electrons (cations)
Why is it negatively charged?
Ex. Oxygen
Gains two electrons
What is the diagram before? After ionization? How would you write it as a symbol?

36. Naming Ions Cations: Anions: Element name + ion Ex. sodium ion
Ex. magnesium ion
Anions:
First part of element name and change ending to “ide”
Ex. nitride
Ex. oxide
Ex. fluoride

37. Practice
For each of the following ions, draw with nucleus and electrons and give appropriate name or symbol:
Hydrogen ion
Cl-
Nitride
Be2+
sulfide

38. Ion Trends in Periodic Table
group 1 = 1+
group 2 = 2+
group 3-12 labeled on table
group 15 = 3-
group 16 = 2-
group 17 = 1-
group 18 not ions
B, C, Si do not form ions

39. Why form ions? Why do atoms gain or lose electrons?
To have full energy levels and be more stable like closest noble gas
Once ions are formed:
Electrically charged
What would happen when I bring a cation and an anion together?
Form a bond! How we make compounds between metals and non-metals
Need to form the ion first before a bond can be formed

40. TO DO
Building an Atom Assignment