1. Getting to know the Periodic Table

2. Before getting to know the periodic table
Drawing Bohr Models and electron dot diagrams

3. Bohr Model of the Atom
Neils Bohr developed a model of the atom in which the electrons orbit the nucleus in fixed orbits like the planets orbiting the sun. We now know that rather than fixed orbits the electrons move about the nucleus in an electron cloud. The electron cloud has energy levels just as Bohr’s model did. Each energy level has a specific number of electrons it can hold. The first energy level can hold two electrons, the second energy level can hold 8 electrons, and the third energy level can hold 18 electrons. The formula 2n2 where n is the energy level can be used to determine how many electrons any energy level can hold. There is only a maximum number of electrons an energy level can hold there is no minimum.

4. Bohr Model of the Atom - A representation of all the electrons of an atom
Determine the number of electrons a particular element has - #electrons = #protons
Draw a small circle - this represents the first energy level of an atom and it can only hold 2 electrons
Draw dots on this first circle to represent electrons (no more than two)
If the atom has more than 2 electrons (total) draw a second circle to represent the second energy level. It can hold a maximum of 8 electrons. Add dots to represent the additional electrons.
Continue drawing increasingly larger circles and adding dots for electrons until you have one dot for each electron in the atom.
The total number of dots on all the circles should equal the total number of electrons in the element.

5. Electron dot diagrams
Also known as Lewis dot diagrams or Lewis structures
Are a representation of an atom’s valence electrons
Valence electrons are those electrons located in an atoms outermost energy level
They are the electrons involved in bonding

6. Determine the number of valence electrons, this can be done using the electron configuration or by memorizing based on the atom’s group
Draw the element’s symbol
Place one dot for each valence electron around the symbol
There will never be more than 8 dots

7. N

8. Periodic Table Arrangement
The periodic table is arranged by increasing atomic number.
It is also divided into periods and groups.

9. Periods
Horizontal rows are called periods.

10. Periods
The period number corresponds to the number of energy levels an atom in that period has.
Example: all elements in period 3 (the turquoise) have three energy levels

11. Groups
Vertical columns are called groups.

12. Groups/Families Groups are also called families.
All elements in the same group have the same number of valence electrons.
Elements with the same number of valence electrons have similar properties. Since they have similar properties they are in the same family.

13. Groups/Families
The groups have specific names. There are 5 you must remember:
Group 1 elements are the alkali metals.

14. Alkali Metals 1 valence electrons Extremely reactive
Reactivity increases from top to bottom
Like to give up electrons

15. Groups/Families
Group 2 elements are the alkaline earth metals.

16. Groups/Families
Groups 3 – 12 are the transition metals.

17. Groups/Families
Group 17 are the halogens (sometimes called halides).

18. Halogens 7 valence electrons Highly reactive Like to gain electrons

19. Groups/Families
Group 18 are the noble gases.

20. Groups/families
All elements in the same group have the same number of valence electrons.
Group 1 elements have 1 valence electron.
Group 2 elements have 2 valence electrons.
Group 13 elements have 3 valence electrons.
Group 14 elements have 4 valence electrons.
Group 15 elements have 5 valence electrons.
Group 16 elements have 6 valence electrons.
Group 17 elements have 7 valence electrons.
Group 18 elements have 8 valence electrons.

21. Metals/Nonmetals/Metalloids
The periodic table is divided into metals, nonmetals, and metalloids.
The metals are located to the left of the dark stair stepped line.
The nonmetals are located to the right of the dark stair stepped line.
The metalloids are located along the stair stepped line.

22. Metals/Nonmetals/Metalloids
The metals are colored gray.
The metalloids are colored blue.
The nonmetals are colored beige.

23. Metals Metals are: Shiny General hard Malleable
Good conductors of heat and electricity
Most are solids at room temperature

24. Nonmetals Nonmetals are: Brittle if solid Most are gases
Not good conductors

25. Metalloids Have properties of metals and nonmetals.

26. Periodic Trends: atomic radius
Atomic radius is an indication of atom size
It is actually half of the distance between 2 adjacent nuclei

27. Atomic Radius Trend

28. Atomic Radius
The inner 2 electrons shield the outer electrons from the pull of the nucleus and atoms get larger as you go down a group. And you add an energy level as you go down.
As you go across the periodic table from left to right atoms get smaller because adding additional protons and electrons increases the attraction between the nucleus and electrons

30. Electronegativity
The ability of an atom to attract electrons
Fluorine is the most electronegative element

31. Electronegativity

32. Ionization energy
The energy required to remove an electron.

33. H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Ga Ge As Se Br Kr