Periodic Table

1
Periodic Table

• Trends Definitions

2
How to read the Periodic Table
6 C Carbon 12.011
Atomic Number
Elemental Symbol
Elemental Name
Atomic Mass
3
Periodic Law

• When elements are arranged in order of increasing
  atomic , elements with similar properties appear
  at regular intervals.

4
Chemical Reactivity

• Families
• Similar valence e- within a group result in
  similar chemical properties

5
Periodic Trends are Influenced by

• Energy Level
• Higher energy levels are further from the nucleus
• Charge on Nucleus ( of protons)
• More charge pulls the electrons in closer
• and attract each other more
• Shielding Effect
• Blocking effect

6
Periodic Trends

• Atomic Radius
• size of atom half the distance between two
  nuclei of a diatomic molecule
• Increases to the LEFT and DOWN

7
Atomic Radius

• Why larger going down?
• Higher energy levels have larger orbitals
• Shielding - core e- block the attraction between
  the nucleus and the valence e-
• Why smaller to the right?
• Increased nuclear charge without additional
  shielding pulls e- in tighter

8
Periodic Trends

• First Ionization Energy
• Energy required to remove one e- from a neutral
  atom.
• Increases going UP and to the RIGHT

9
Periodic Trends

• Melting/Boiling Point
• Highest in the middle of a period.

10
Periodic Trends

• Electronegativity
• Tendency of an atom to attract electrons when
  chemically combined

11
Ionic Radius

• Cations ()
• lose e-
• smaller
• Anions ()
• gain e-
• larger

12
Ion Group trends
Li1

• Each step down a group is adding an energy level
• Ions therefore get bigger as you go down, because
  of the additional energy level.

Na1
K1
Rb1
Cs1
13
Ion Period Trends

• Across the period from left to right, the nuclear
  charge increases - so they get smaller.
• Notice the energy level changes between anions
  and cations.

N3-
O2-
F1-
B3
Li1
Be2
C4
14
Size of Isoelectronic ions

• Iso- means the same
• Isoelectronic ions have the same of electrons
• Al3 Mg2 Na1 Ne F1- O2- and N3-
• all have 10 electrons
• all have the same configuration 1s22s22p6
  (which is the noble gas neon)

15
Size of Isoelectronic ions?

• Positive ions that have more protons would be
  smaller (more protons would pull the same of
  electrons in closer)

N3-
O2-
F1-
Ne
Na1
Al3
7
10
9
8
11
13
12
Mg2