Periodic Trends

1
Periodic Trends
2
Shielding Effect

• Inner electrons electrons between the nucleus
  and the outermost energy level.
• The inner electrons shield the valence electrons
  (outermost electrons) from the positive charge of
  the nucleus.
• This causes a reduction in attraction between the
  nucleus and the valence electrons so that the
  valence electrons are held more loosely.

3
Shielding Effect
Increases
Stays the same
4
Atomic Radius

• The atomic radius is the distance from the atomic
  nucleus to the atoms outer surface.
• The atomic radius gets gradually smaller with
  increasing atomic number.

5
Trends in Atomic Size
6.3
6
Ions
Positive Ion

• An ion is a charged atom. Ions have unequal
  numbers of electrons and protons.
• If a neutral atom loses electrons, its protons
  will outnumber its electrons. (Positive Ion)
• If a neutral ion gains electrons, its electrons
  will outnumber the protons. (Negative Ion)
• Positive Ions are called Cations (metals)
• Negative ions are called anions (nonmetals)

Negative Ion
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Ionic Radius

• When metals lose electrons they become smaller
  due to the nuclear charge being larger than the
  number of electrons. Electrons are held tighter.
• When nonmetals gain electrons they become larger
  due to the nuclear charge being less than the
  number of electrons. Electrons are held looser.

8
Trends in Ionic Size
6.3

• Trends in Ionic Size

Size generally increases
9
Ionization Energy

• the amount of energy required to pull an electron
  away from an atom to form a positively charged
  ion.

10
Trends in Ionization Energy
6.3
11
Electronegativity

• Electronegativity is thought of as an atoms
  electron pulling power.

12
Electronegativity

• The greater an atoms electronegativity, the
  greater its ability to pull electrons towards
  itself when bonded.
• .
• Fluorine has the highest electronegativity.

13
Trends in Electronegativity
INCREASES
Decreases