1. Getting to Know the Periodic Table

2. a big part of science is about looking for patterns and then classifying and understanding matter according to those patterns
we classify matter as solid, liquid or gas
we classify matter as pure substances or mixtures
e.g.

3. in ancient times chemists used symbols of the Sun and planets to represent the 7 metallic elements known at the time
by the early 1800s 30 elements were known → John Dalton, an English chemist, tried to make a better system of symbols

4. Why was this idea better than continuing to use Dalton’s symbols?
in 1814 a Swedish chemist Jöns Jacob Berzelius suggested using letters rather than pictures to represent elements
many letters are quite obvious
e.g. C = carbon O = oxygen N = nitrogen
Why was this idea better than continuing to use Dalton’s symbols?

5. but what happened when a letter was already used?
e.g. H = hydrogen… and along comes helium
e.g. or C = carbon… but then there are calcium, cobalt, chromium, chlorine…
and what about elements that seem to have random symbols?

6. remember that Latin was the original language of science… and many symbols are based on an elements’ Latin name

7. Write your Name in Symbols
what would your name look like in symbols?
remember, each letter can only be used 1 time as a capital … the next time it must have a 2nd lower case letter adjacent to it
what element would you be?
MS. MoRRiSoN

8. Law of Octaves by the mid 1800s 63 elements were known
an English chemist John Newlands recognized a pattern
when elements were listed in order of increasing atomic mass he saw that the properties of the elements seemed to repeat at regular intervals
he called this pattern the “law of octaves”
other scientists though he was silly and refused to accept his ideas 

9. Mendeleev
shortly after, a Russian chemist, Dmitri Mendeleev, made up cards with properties … such as melting point, density & colour… for each known element
he arranged them by atomic mass and then based on repeating patterns of properties
he noticed gaps and predicted new elements would some day be discovered to fill the gaps
again scientists laughed but within 16 years elements had been discovered to fill all the gaps in Mendeleev’s patterns

10. The Periodic Table

11. the periodic table consists of 18 columns called groups (or families) and 6 rows called periods
there are patterns which exist within the groups or families… and within the periods

12. The Elements
every element on the periodic table has its own box which contains useful information
Atomic Number = # protons
Atomic Mass = # protons + # neutrons

13. most elements are solid at room temperature
some are gas
only 2 are liquid – bromine (Br) & mercury (Hg)

14. Metalloids
can have properties of either metals or non-metals
semi conductors
Non-Metals
solid or gas (at room temp)
solids are dull & brittle
non-conductive (except C)
will not react to acid
Metals
most common elements
solid (at room temp)
shiny & malleable
ductile
conductive
will react to acid
insulators
conductors

15. Reactivity of Metals
Reactivity Increases
Reactivity Increases

16. Reactivity of Non-Metals
Reactivity Increases
Reactivity Increases
Except… Group 18… the Noble Gases… are non-reactive

17. Characteristics of Families
Group 1 – Alkali Metals
most reactive metals
shiny and light weight
react very strongly to explosively when exposed to air or water
Group 2 – Alkaline Earth Metals
2nd most reactive metals
when mixed in solution pH > 7 (basic or alkaline)
react strongly when exposed to air or water

18. Group 17 – Halogens
most reactive of non-metals
often bond with elements of group 1
Group 18 – Noble Gases
most stable and unreactive elements
generally will not form compounds with other elements
they are pretty rare

19. But what about H
H does not belong to any family… even though it sits above the alkali metals (family 1)
it is the simplest and lightest element → and also the most common one … over 90% of all atoms in the Universe are H
it is an odorless and colorless gas
it burns readily, with a near invisible flame
on Earth it is almost always found in water … any free H is so light it cannot be held by Earth’s gravity
the name comes from the Greek – hydro (water) and genes (forming) → hydrogen is one of the two water-forming elements

20. Extra Stuff Video Summary of Periodic Table
Link to Videos for Each Element