Download The Periodic Table

Development of the Periodic Table
Mendeleev Constructed the first periodic table
according to the
similarities in each element’s properties
- He arranged them in order of atomic masses
- He left blank spaces in his periodic table
because there were no known elements with the
appropriate properties and masses.
Later Mosley rearranged the periodic table by atomic
number
The Modern Periodic Table
Periodic Law: When elements are arranged in order of
atomic number, there is a repetition of their physical and
chemical properties
Groups or Families: vertical columns. Group numbers
are indicated with a number and a letter A or B
- Elements within a group have similar physical and
chemical properties
- Group A elements are the representative elements
because they exhibit a wide range of chemical
and physical properties
Where are things located on the
Periodic Table?
Metals →
←
Nonmetals
The light blue elements are semimetals
Properties of Metals:
- They make up 80% of the elements
- All metals except for one is a solid at room temperature
- One the big periodic table solids are black, liquids are
blue, and gases are red
- They have a metallic luster
- They are good conductors of electricity
- They are malleable
- They are ductile
Properties of Nonmetals
- They lack luster
- They are brittle
- They are poor conductors of electricity (insulators)
Properties of Semimetals
- They have some of the characteristics of metals and
some of nonmetals
Periodic Trends
Atomic Radius: The distance from the center of the
nucleus of an atom to the outer edge of
that atom
As you go to the left and down the periodic table
the atomic radius tends to increase.
Why does the atomic radius decrease if we are
adding another proton and electron
when we move to the right?
Think as the principle quantum energy level of an
atom as an amount of space.
- As you move down the periodic table you add
more space and make the atomic radius larger
- As you move from the left to the right there is the
same energy level (amount of space) but we
add another proton and electron
- This makes more attraction between these
particles and contracts the atom
Ionic Radius: The distance from the center of the
nucleus of an ion to the outer edge of
that ion
- As you go to the right and down the periodic
table the ionic radius tends to increase.
- The parent atoms of positive ions are always
larger than the ion.
- Because an energy level is lost and the
protons have an even greater pull
on the electrons
- The parent atoms of negative ions are always
smaller than the ion because they gain
electrons
Ionization Energy: the amount of energy required to
remove the outermost electron
- The higher the number the harder it is to take
away an electron
Electronegativity (Electron Affinity): The
attraction that an atom has for electrons.
- This is the reason that atoms form bonds