1. Arrangement of the Periodic Table

2. Vertical columns Called groups or families
Contain elements with similar chemical and physical properties

3. Horizontal rows Called periods
The length of a period is determined by the number of electrons that can occupy the orbitals filled in that period
Properties vary as you move across a period

4. The table is arranged in blocks – s,p,d, and f
Based on the electron configuration of each element
The highest occupied energy level is the period in which the element is found

6. s-block elements
The s-block elements include groups 1 and 2 as well as hydrogen and helium.

7. Group 1 Alkali metals Silvery in appearance
Soft enough to cut with a knife
Very reactive
Not found in nature as free elements
Combine vigorously with most non-metals and water
When isolated, they must be store in kerosene to prevent them from reacting with air or moisture

8. Group 2 Alkaline-earth metals Pair of electrons in outermost s orbital
Harder, denser, stronger than alkali metals
Less reactive than alkali metals, but still too reactive to be found in nature as free elements

9. Hydrogen and Helium
Hydrogen does not share the same properties as the elements of group 1. It is a unique element with properties that don’t resemble those of any group.
Helium has its outermost energy level full with just 2 electrons. It is placed in group 18 with the other elements with full outer shells (noble gases)

10. d-block elements Transition elements (or transition metals)
Good conductors, high luster
Less reactive than group 1 or group 2 metals
Some are so unreactive that they rarely form compounds
Palladium, platinum, and gold are among the least reactive

11. p-block elements
All have a full s-orbital in outermost energy level, and at least one electron in a p orbital.
Properties vary greatly
Include metals (left and bottom of block)
Nonmetals (right side)
Metalloids (boron, silicon, germanium, arsenic, antimony, and tellurium)

12. The metals of the p-block are harder and denser than the alkaline earth metals, but softer and less dense than the transition metals.

13. The metalloids are mostly brittle solids with some properties of metals and some of nonmetals.
Electrical conductivity is in between that of metals and nonmetals – they are called semiconductors.

14. All the nonmetals except hydrogen and helium are found in the p block.
They include the halogens and the noble gases.

15. Halogens The halogens are group 17.
They are the most reactive nonmetals
React vigorously with most metals to form salts.
At room temperature, fluorine and chlorine are gases, bromine is a reddish liquid, and iodine is a dark-purple solid.

16. Noble gases
Group 18
Nonreactive because their outermost energy level is full with an octet of electrons.
Except helium which is full with just 2 electrons

17. f-block elements Lanthanides and actinides
Fall between groups 3 and 4, but do NOT belong to any group themselves.
Lanthanides are shiny metals which are similar in reactivity to the alkaline earth metals
Actinides are all radioactive and all but the first 4 are synthetic.