History of the Periodic Table

1
History of the Periodic Table

• What did Cannizzaro Do?
• Developing a method that led to the determination
  of standard relative atomic masses, which allowed
  chemists to search for periodic trends among
  elements

2
What did Mendeleev do?

• Discovered the periodic law
• Organized the elements according to increasing
  atomic mass and noticed that similar properties
  appeared periodically.
• What is the periodic law?
• The physical and chemical properties of the
  elements are periodic functions of their atomic
  numbers
• Demostrated in the periodic table because groups
  have similar chemical and physical properties and
  behavior

3
What did Mosley do?

• Discovered that nuclear charge(atomic number) not
  atomic mass, should be the basis for organizing
  the periodic table

4
How do the electron configuration within the same
group compare?

• The configurations of the outermost electron
  shells of elements within the same group are the
  same. There are a number of exceptions to this
  rule, in the transition elements

5
What determines the length of each period in the
periodic table?

• The length of a period is determined by the total
  number of electrons that can fill the outer
  sublevel of the elements of that period

6
What is the relationship between the electron
configuration of an element and the periods in
which that element appears in the periodic table

• An elements period corresponds to its highest
  occupied main energy level.

7
What information is provided by the specific
location of an element?

• The type of sublevel being filled in successive
  elements of that block
• S block groups 1 and 2
• P block groups 13-18 except He(s)
• D block groups 3-12
• F block lanthanide and actinide series

8
What are properties of the Group 1 Alkali Metals?

1. Extremely reactive
2. react vigorously with water
3. Silvery in color
4. Soft enough to be cut with a knife
5. All have 1 valence electron

9
What are the properties of Group 2 Alkaline
earth metals

1. Less reactive than group 1 elements
2. Harder, denser, stronger than group 1
3. Higher melting points than group 1
4. 2 valence electrons

10
What type of elements make up the P block of the
periodic table?

• Nonmetals at the right
• Metalloids on the stairs
• Metals under the stairs these metals are
  generally ahrder and more dense than the s block
  metals but softer and less dense than the d-block
  metals

11
What are properties of the Group 17halogens?

• Most reactive nonmetals
• Fluorine is the most reactive of all nonmetals
• React vigorously with most metals to form salts
• Most electronegative elements.

12
What are the properties of the metalloids? B, Si,
Ge, As, Sb,Te

• Mostly brittle solids with electrical
  conductivities intermediate between those of
  metals (good conductors) and nonmetals (poor
  conductors)

13
What are the main group elements and what trends
can be seen across periods of these groups

• s and p group elements
• Decrease in atomic size
• Increase in ionization energy
• Increase in electron affinity
• Decrease in cationic size
• Decrease in anionic size
• Increase in electronegativity

14
What is ion?A charged atom or a charged group of
bonded atoms

• What is ionization?
• Any process that results in the formation of
  bonded atoms
• What is first ionization energy?
• The energy required to remove one electron from a
  neutral atom of an element.
• What is second ionization energy?
• The energy required to remove an electron from a
  1 ion.

15
How do the first ionization energies of main
group elements vary across a period and down a
group?

• Increase across a period and decrease down a
  group.
• Across a period, the increasing nuclear charge
  more strongly attracts electrons in the same
  energy level and makes them more difficult to
  remove
• Down a group, the electrons to be removed from
  each successive element are in increasingly
  higher energy levels farther from the nucleus and
  are more easily removed

16
What is electron affinity?

• The energy taken in or given off when an electron
  is added to an atom
• Electron affinity values are either negative or
  positive. A negative sign shows that energy is
  given off and a positive sign show energy is
  taken in

17
What is the difference between a cation and an
anion

• Cation positive ion and a metal
• Anion negative ion and a nonmetal
• Cations are always smaller than the atoms they
  came from
• Anions are always larger than the atoms they came
  from