- Dmitri Mendeleev organized the elements into the periodic table based on their atomic mass and recognized repeating patterns in their properties. He left space for undiscovered elements. - Henry Moseley determined that atomic number, the number of protons, allowed elements to be organized into a definite pattern according to the periodic law where chemical and physical properties repeat periodically with increasing atomic number. - The periodic table arranges elements by atomic number and provides information on each element including name, symbol, atomic number, atomic mass, and whether they are metals, nonmetals, or metalloids.

1. Periodic Table
Fusion: Unit 5, Lesson 2
Holt: Chapter 12
1st Quiz: Thursday, 12/4/14

2. Periodic Table
• Dmitri Mendeleev-recognized that
elements had repeating patterns (periodic)
and organized elements into a table by
increasing atomic mass
• Predicted and left space for unidentified
elements

3. • Henry Moseley - determined that the
number of protons - atomic number (which
is unique to each element) would allow the
elements to fit into very specific pattern
• All identified elements follow the periodic
law – chemical and physical properties
change periodically with atomic number

4. Metals
• Most elements are
metals
• Found to the left of
the zigzag line
• Solid at room temp
(exception: mercury
and hydrogen –
nonmetal)
• Properties:
– Shiny
– Ductile
– Malleable
– Good conductors

5. • Also called Metalloids
semiconductors
• Border the zigzag line
(exception Al)
• Have properties of
both metals and
nonmetals depending
on the conditions
• properties: depending
on conditions
– Brittle
– Good conductors
– Some shiny (others
dull)

6. Nonmetals
• More than half are
gases at room temp
• To the right of the
zigzag line
• Properties:
– Not malleable or
ductile
– Not shiny or dull
– Poor conductors

7. • Each square includes:
• elements name
• chemical symbol
(color coded to
identify if element is a
solid, liquid or gas at
room temp)
• Atomic number
(protons)
• Atomic mass
(weighted avg)
• Background color
(identifies metals,
nonmetals and
metalloids on table)

8. REVIEW
• Atomic number = Number of Protons
• Electrons equal to the number of protons
• Neutrons equal atomic mass (rounded)
minus the protons
• Protons do not change in a atom,
neutrons can change, electrons can be
shared or transferred (when bonds are
made)

9. • First letter of chemical symbol is always upper
case and any additional letters are lower case
• Newest elements have temporary 3 letter
symbols
• *****Rows (left to right) are called periods-determines
the number of energy levels
• Properties gradually change moving left to right
across each row from reactive (group 1) to non-reactive
(group 18)

10. • Columns are called groups or family
• Elements in the same group or family have
similar properties moving up and down each
column
• Each element in a family has the same number
of valence electrons in the outer shell
• ******Group number determine the valence
electrons (ex: group one – all elements in group
1 have 1 valence electron, all of the elements in
group 2 have 2 valence and so on)

11. Group 1: Alkali metals
• Metals
• 1 valence electron in
outer level (easily
shared and form
compounds easily)
• Very reactive with
H2O, O2 and other
elements
• Don’t appear in
nature by themselves,
only as compounds

12. Group 2 – Alkaline-Earth Metals
• Metals
• 2 valence electrons in outer level (slightly
less reactive)

13. Group 3 – 12: Transition
• Metals
• 1 or 2 valence electrons in outer level
(depending on element) and are less
reactive

14. Lanthanides and Actinides
• In periods 6 and 7
and appear at the
bottom of the periodic
table to keep table
from being too wide
• Lanthanides are shiny
reactive metals
• Actinides are
unstable; radioactive
• All elements after Pu-94
(plutonium) are man-made
in labs and don’t
occur in nature

15. Group 13: Boron Group
• Has 1 metalloid and 4 metals
• 3 valence electrons in outer level and are
semi reactive

16. Group 14 - Carbon group
• 1 nonmetal, 2 metalloids and 2 metal
• 4 valence electrons in outer level and
most non-reactive depending on element
• Forms organic compounds (all living
things contain carbon)

17. Group 15 - Nitrogen Group
• 2 nonmetals, 2 metalloids, 1 metal
• 5 valence electrons in outer level and
reactivity depends on conditions and
element
• P is extremely reactive and only appears
in compounds

18. Group 16 - Oxygen Group
• 3 nonmetals, 1 metalloid, and 1 metal
• 6 valence electrons in outer level and
reactivity depends on element
– Po-84 is radioactive

19. Group 17 - Halogens
• Nonmetals
• 7 valence electrons in
outer level and has
violent reactions with
alkali-metals to form
salt compounds
– Highly reactive with
other elements
– Do not appear in
nature alone only in
compounds

20. Group 18 - Noble Gases
• Nonmetals
• 8 valence electrons in
outer level (full level)
(except helium which
has 2 valence
electrons, which
makes helium full)
and very un-reactive
– inert
• Do not form
compounds under
normal conditions

21. Hydrogen
• Nonmetal
• 1 electron in outer level so it is set above
the alkali metals and is reactive
• Properties: even though above metal
category, has properties of nonmetals
• Most abundant element in universe,
makes up stars

22. Energy Levels
• 1st energy level – 2 valence electrons (max)
• 2nd energy level – 8 valence electrons (max)
• 3rd energy level – 8 valence electrons (max)
• And so on….
• Each energy level can have less valence
electrons but they can not have more than
the maximum valence electrons.

23. Bonds
• To form bonds, elements must reach a full
state of 8 valence electrons in the
outermost energy level (octet rule)
(Exception: would be first energy level
which is full at 2-helium)