1. -Describe how elements are arranged in the periodic table
Arranging elements
Objectives:
-Describe how elements are arranged in the periodic table
-Compare metals, non-metals and metalloids based on their properties and their location in the periodic table.

2. Organizing the elements according to their properties would help scientists understand how elements interact with each other.

3. Mendeleev’s Periodic Table
In 1869, a Russian chemist and teacher published a table of the elements.
Mendeleev arranged the elements in the periodic table in order of increasing atomic mass.

4. The Periodic Law
In the modern periodic table elements are arranged in order of increasing atomic number.
Periodic Law states: When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

5. The periodic table is made up of rows of elements and columns.
An element is identified by its chemical symbol.
The number above the symbol is the atomic number
The number below the symbol is the rounded atomic mass of the element.
A row is called a period
A column is called a group

6. The elements can be grouped into three broad classes based on their general properties.
Three classes of elements are Metals, Nonmetals, and Metalloids.

7. Properties of Metals
Metals are good conductors of heat and electricity.
Metals are shiny.
Metals are ductile (can be stretched into thin wires).
Metals are malleable (can be pounded into thin sheets).
A chemical property of metal is its reaction with water which results in corrosion.
Solid at room temperature except Hg.

8. Properties of Non-Metals
Non-metals are poor conductors of heat and electricity.
Non-metals are not ductile or malleable.
Solid non-metals are brittle and break easily.
They are dull.
Many non-metals are gases.
Sulfur

9. Properties of Metalloids
Metalloids (metal-like) have properties of both metals and non-metals.
They are solids that can be shiny or dull.
They conduct heat and electricity better than non-metals but not as well as metals (Semiconductors)
They are ductile and malleable.
Silicon

10. Grouping the Elements Objectives
Describe the difference between period and group.
Explain why elements in a group often have similar properties.
Describe the properties of elements and the groups of the periodic table.

11. The properties of the elements in a group are similar because the atoms of the element have the same number of electrons in their outer energy level.
What are energy levels?

12. Energy level refers to how the electrons are configured in an atom or molecule.

13. Atoms will often take, give, or share electrons in their outer energy level.
Elements whose undergo such processes are called reactive and can form compounds.

15. Hydrogen
The hydrogen square sits atop group 1, but it is not a member of that group. Hydrogen is in a class of its own.
It’s a gas at room temperature.
It has one proton and one electron in its one and only energy level.
Explosive reactions with oxygen
Used as fuel in rockets

16. Four chemical groups of the periodic table:
alkali metals (1)
alkaline earth metals (2)
Transition Metals (3-12)
Boron group (13)
Carbon group (14)
Nitrogen group (15)
Oxygen group (16)
Halogens (17)
Noble gases (18)

17. Alkali Metals
The alkali family is found in the first column of the periodic table.
Atoms of the alkali metals have a single electron in their outermost level, in other words, 1 valence electron.
They are shiny, have the consistency of clay, and are easily cut with a knife.

18. Alkali Metals
They are the most reactive metals because their atoms can easily give away the one outer-level electron
They react violently with water and form hydrogen gas.
Alkali metals are never found as free elements in nature. They are always bonded with another element.

19. Alkaline Earth Metals They have two valence electrons.
Alkaline earth metals include magnesium and calcium
Magnesium can be mixed with other metals to make low-density materials used in airplanes.

20. Transition Metals
Transition Elements include those elements in the groups 3-12
These are the metals you are probably most familiar with: copper, tin, zinc, iron, nickel, gold, and silver.
They are like metals, shiny and good conductors of heat and electricity.

21. Transition Elements
Open page 346

22. Boron Group Have 3 valence electrons Reactive
Solids at room temperature
Most common element is Aluminum

23. Carbon Group Have 4 valence electrons Solids at room temperature
Reactivity varies among elements
Carbon is essential for living organisms since it forms a wide range of compounds such as fats, proteins and carbohydrates.

24. Nitrogen Group Have 5 valence electrons
Reactivity varies among elements
Solids at room temperature except for Nitrogen.
Nitrogen makes up 80% of the air you breathe.

25. Oxygen Group Have 6 valence electrons. Reactive
Solids at room temperature except for oxygen
Oxygen is crucial for all living organisms.
Sulfur is used to make sulfuric acid, the most common compound in the chemical industry.

26. Halogens Nonmetals Have 7 valence electrons
Very reactive since they need just one electron to have a complete outer level.
Usually react with metals to gain the missing electron.
The reaction of halogen with metal makes a salt.
Chlorine and iodine are used as disinfectants.

27. Noble gases
Nonmetals
complete outer energy level, 2 valence electrons in Helium and 8 in the rest
Un-reactive
Colorless, odorless gases at room temperature
Neon is used to make “neon” lights

28. Page 351 questions 1-10