Periodic Table: Trends - Weebly
Transcript of Periodic Table: Trends - Weebly
Periodic Table: Trends
Atomic Radius
Down a group:AR ↑ because # of energy levels ↑
Across a period: Right to leftAR ↑ because of ↓ in p+ attraction to surrounding e-
Increasing
Increasing
1716 18
Increasing atomic radius
16 p+ in nucleus16 e- in 3 energy levels
Same Period on Periodic Table17 p+ in nucleus
17 e- in 3 energy levels18 p+ in nucleus
18 e- in 3 energy levels
SOME attraction between p+ in nucleus and e-
Large atom
MORE attraction between p+ in nucleus and e-
Smaller atom
MOST attraction between p+ in nucleus and e-
Smallest atom
Trend in Atomic Radius
BIGGEST
Atomic Radius Examples
Which element is larger? Explain. Silicon or Sulfur
Which element is smaller? Explain. Barium or Zirconium
Zr has 5 energy levels, Ba has 6, so Zr is smaller
Silicon’s p+ don’t attract the e- as close as Sulfur’s p+ do
NaMetalValence e-: 1
ClNonmetal
Valence e-: 7
Ionic radius vs Atomic Radius
Now Na has a +1 charge…smaller radius
And Cl has a -1 charge…larger radius
Cation < Atom < AnionFor radius:
Ionization Energy (IE) The energy required to remove one valence
electron from an atom to make a cation.
F
Kr
Be
C
Ionization Energy (IE)
Up a group: IE ↑ because # of
energy levels ↓ (more p+ and e- attraction)
Across a period: IE ↑ because of # of
valence e- increases
Ionization Energy
Increasing
Trend in Ionization EnergyHIGHEST
Ionization Energy: Examples
Which element has a higher ionization energy? Explain. Silicon or Sulfur
Which element has a lower ionization energy? Explain. Barium or Zirconium
S requires more E to remove an e-
because has 6 val e-, close to desired 8
Ba has more energy levels, so easier to take an e- away than Zr
The ability for an atom to attract electrons in a chemical bond (atoms strength)
Related to # of valence electrons
Related to p+ and e-
attraction
Electronegativity (EN)
F
H
Electronegativity (EN)
Increasing
Increasing
Up a group:EN ↑ because #
of energy levels ↓ (more p+ and e-
attraction)
Across a period: EN ↑ because
of # of valence e- increases
Trend in Electronegativity
HIGHEST
DO NOT include Noble Gases (don’t bond)
Electronegativity Examples
Which element is more electronegative? Explain. Silicon or Sulfur
Which element is less electronegative? Explain. Barium or Zirconium
S wants more e- because has 6 val e- only needs 2 more
Ba has 1 more energy level, so less attraction with highest energy e-