THE GREATEST TABLE ON EARTH!!!The Periodic Table of Elements
Periodic Table
Ever wondered: Why the Periodic Table is shaped the
way it is? Why is it called the Periodic Table? Why are there 2 disconnected rows? What information does it have?
Well today is your lucky day, because we are about to find out!
Periodic Table
The Periodic Table of the Elements shows every known type of atom.
It contains a large amount of information
Much of the information we can get just from the organization and shape of the periodic table
The Beginning The Periodic Table was first made in
1869 by a Russian named Dmitri Mendeleev
His table looked something like this:
What do you notice about his periodic table?
Mendeleev’s Periodic Table
Mendeleev ordered the elements by their atomic mass (he didn’t know protons existed yet)
He grouped those similar elements into columns He started a new column every
time the physical or chemical properties changed
Mendeleev left spaces for new, undiscovered elements and tried to predict their properties
Mendeleev’s Periodic Table As years went on, several elements
were discovered Their properties were nearly
identical to those that Mendeleev predicted
Eka-aluminium (Ea)
(Mendeleev’s Prediction)
Gallium (Ga)
(Discovered Element)
Atomic weight About 68 69.72
Density of solid 6.0 g/cm3 5.9 g/cm3
Melting point low 29.78oC
Valency 3 3
What Mendeleev’s Predictions Tell Us?
Mendeleev showed us there are patterns and trends to the elements
These patterns show us we can organize the elements by their properties
Atomic Number
The most obvious way that the periodic table is organized by increasing atomic number
However, this doesn’t explain why the elements are grouped the way they are
Atomic Mass
The atomic mass also increases (generally) as the atomic number increases
This, also, does not explain the element groupings
Periods
Rows on the periodic table are called periods
Periods
Elements are organized into periods based on where their electrons are
The outermost orbital filled by electrons determines what period an element is in If an elements outermost electrons are in the
1st orbital, the element is in the 1st period If an elements outermost electrons are in the
4th orbital, the element is in the 4th period
Groups The vertical columns of the periodic
table are organized by common physical and chemical properties
Why do you think these groups have similar properties?
Groups
Draw an atom of hydrogen, lithium, and sodium.
What do you notice about each of these atoms?
Groups Each atom has 1 electron in it’s outside
orbital Remember that electrons determine an
atoms behaviour Since each atom has the same
number of electrons in its outside orbital, they all behave the sameH Li Na
Groups
This outside orbital is the same for every atom in a group
This means that atoms in a group behave pretty much the same
Now let’s take a look at some notable groups
Group 1
Group 1 are called alkali metals They include the entire first column
(excluding hydrogen) They all:
Are soft, shiny, grey metals Are extremely reactive Have low densities, low hardness, and low
boiling points All burn with red, pink, or yellow colours
Group 2
Group 2 are called Alkali Earth Metals
Includes Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium
All are somewhat shiny, silvery-white, and are much harder than group 1
All make strong bases when mixed with water
Are about twice as dense as group 1
Group 17
Group 17 are called halogens Contains Fluorine, Chlorine, Bromine,
Iodine, and Astatine All are extremely reactive All are extremely dangerous to living
things (except iodine) All make acids with hydrogen All are vividly coloured
Group 18
Group 18 are called the Noble Gases
They include helium, neon, krypton, argon, xenon, and radon
Are all gases All do not react at all All glow with bright colours when
electricity is passed through them
Metals to Non-metals
The periodic table also organizes metals all the way to what are called non-metals
Metals are materials that: Have a shiny lustre Conduct electricity Conduct heat Are malleable
Transition Metals
The transition metals go from group 3 (scandium group) to group 12 (zinc group)
They are all conductors of electricity and heat
They all have a shiny lustre
Transition Metals
They are all malleable
They are all silver except for gold and copper
The only 3 magnetic elements are in the transition metals Iron Cobalt Nickel
Poor Metals
Poor metals are in group 13, 14, 15, and 16
Below the ‘staircase’ Are very malleable Very soft Poor electrical conductors Low boiling points
Non-metals
Non-metals do not conduct electricity or heat
Have a dull lustre (mostly) Are brittle Not malleable Exist as solids, liquids, and gasses Most are brightly coloured
The ‘Staircase’
Between the poor metals and the non-metals is a staircase
This line shows a separation between elements that act like metals and elements that don’t
Metalloids
Elements along the staircase are called metalloids
They act like metals and non-metals
Includes boron, silicon, germanium, arsenic, antimony, tellurium, and polonium
Metalloids Metalloids conduct some electricity
The hotter they are, the more conductive they are
Somewhat brittle Shiny lustre Make computers possible
Lanthanides & Actinides
The ‘disconnected’ rows of the periodic table are called the lanthanides and actinides
They are all radioactive
All are very reactiveLanthanides
Actinides
Blocks New information about how electrons work
has taught us about things called shells The periodic table is also organized by
which electron shell is furthest to the outside of an atom There are 4 shells
S – shaped like spheres P – shaped like dumbbells D – many shapes F – many shapes
Groups All atoms in the ‘s’ block have their outer most
electrons in the ‘s-shell’
All elements in the ‘d’ block have their outer most electrons in the ‘d-shell’
And so on…