1. Periodic Table

2. Elements What is an element?
Substance that cannot be broken down into simpler substance
Atom – smallest unit of matter that has the properties of an element
Elements are composed of atoms that have a specific number of protons

3. Organizing the elements
In the 1800’s, chemist Dimitri Mendeleev wanted to organize the known elements by their properties

4. Mendeleev Organized the elements by increasing mass
All the elements in a column have similar properties
He left holes in the table for elements that had yet to be discovered

5. Modern Periodic Table

6. Modern Periodic Table Element Squares
Element Name
Atomic Number
number of protons
Chemical Symbol
Represents the element
One or two letters
Not always the same letters as in the element name
Average Atomic Mass
Mass of an atom of the element
Average of all known isotopes on Earth
Grams/mole

7. Modern Periodic Table Organization
Metals
Good conductors
Malleable
Mostly all solid
Nonmetals
Poor conductors
Brittle
Many are gases
Metalloids
Have properties of both metals and nonmetals

8. Modern Periodic Table States of matter

9. Modern Periodic Table Organization
Period – row across the table
Atomic number increases left to right
Period Number = number of orbitals in the atom

10. Drawing atoms Bohr Model
Draw a small circle in the middle
Number of protons
Number of neutrons
Draw a ring around the circle for each orbital
Add electrons starting closest to the center (first orbital)
First orbital holds 2 electrons
Second orbital holds 8 electrons
Third orbital holds 8 electrons

11. Bohr model atom What can we learn about an atom from these drawings?
Number of Protons
Number of Neutrons
Mass number
# of protons + # of neutrons
Number of electrons
Number of valence electrons
Charge of the atom
Charge of protons + charge of electrons
Ion or not

12. Bohr model atoms practice
Draw the following atoms, name the element, and determine the charge and mass
5 protons, 4 electrons, 4 neutrons
7 protons, 10 electrons, 7 neutrons

13. Bohr model atoms practice
Draw the following atoms and determine the number of protons and electrons
Sodium, neutral charge, one more proton than neutron
Nitrogen, -3 charge, #protons=#neutrons

14. Modern Periodic Table Organization
Family/Group
columns up and down

15. Properties Related to Groups
These Properties do not apply to the middle section
Oxidation Number
Reactivity
Valence Electrons

16. Properties Related to Groups Oxidation Number
The number of electrons an atom is willing to gain or lose
Plus = more likely to lose an electron
Minus = more likely to gain an electron
Oxidation number:

17. Properties Related to Groups Reactivity
How likely an atom is to react with another atom
Groups 1 and 17 - most reactive
Group 4 – least reactive
Group 18 - not reactive at all

18. Reactivity of Elements
Alkali metals
Halogens

19. Properties Related to Groups Valence Electrons
electrons found in the outermost orbital
Group 1: 1 VE
Group 2: 2 VE
Group 13: 3 VE
Group 14: 4 VE
Group 15: 5 VE
Group 16: 6 VE
Group 17: 7 VE
Group 18: 8 VE
Valence Electrons:

20. Drawing Atoms Lewis Dot Structure
Write the chemical symbol
Draw valence electrons around the symbol
Drawing electrons:
Draw one dot on each side of the symbol if ≤ 4 valence electrons
Pair electrons if 5-8 valence electrons
Exception: Helium

21. Lewis Dot Structure
What can we learn about an atom from these drawings
Element name
Valence electrons
Practice Worksheet

22. Naming Families Group 1: Alkali Metals Group 2: Alkaline Earth Metals
Groups 3-12: Transition Metals
Group 13: Boron Family
Group 14: Carbon Family
Group 15: Nitrogen Family
Group 16: Oxygen Family
Group 17: Halogens
Group 18: Noble Gases
Lanthanide Series
Actinide Series