periodic trends Flashcards
Whats atomic radius definition?
The size of an atom from its ncleus to the outermost shell/outer perimeter.
What is the trend ot atomic radius?
As you go down a period atomic radius gets bigger (increases)
From left to right atomic radius atomic radius decreases.
Why does the atomic radius trend happen like this?
Top to bottom =
More shells, further distance from nucleus and less attraction/ “weaker pull”
+
Inner electrons block the attraction from the nucleus to the outer electrons
Left to Right =
# of protons increase
–> NOTE: Even though the number of electrons increase from left to right, they are added to the shame shell, therefore there is no additional sheilding.
Ionization What is it
The quantity of energy to remove an electron from an atom or ion in a gas state (Kj/mol)
Whats the ionization trend??
Top to Bottom = Decrease IE
Left to right = Increase in IE
Explain the Ionization trend??
Top to bottom:
-> More sheilding = less energy needed to remove ion
-> Bigger atom = less energy (less pull/attraction)
Left to right:
-> Smaller atomic radius (= strong attraction, due to increased pull)
->More attraction = harder to remove electrons, therefore requires more energy
Ionization energy levels Explain
The first ionization energy requires the least amount of energy (removes the most loosely held electrons)
The second ionization energy removes the second loosly held electron, etc.
What is ionic radius
The distance from the nucleus to the outermost electron in the ION.
–> An of an atom when it loses or gains an eletron.
Whats the ionic Radius trend (Why)
Cations –> Smaller radius:
- Metals lose an electron/ therefore more protons than eletrons (More attraction = more pull)
Anions –> Larger radius:
-Non-metals gain an electron
-Completed energy level
-More electrons = more repulsion (Pushing them further a part)
Splitting the periodic table into two:
–> Left to right Both anions and cations decrease in size
Down a group:
Attomic radius increases, because more shells.
Anions are always bigger than cations from the same period.
Note:
Higher positive charge = smaller radius
Higher negative charge = larger radius.
Electron affinity definition:
-> The energy changed/released that occurs when an electron is added to a neutral atom in a gas state. (Kj/Mol)
Electron affinity trends:
Left to right: EA increases
Top to bottom: EA decreases
Explain EA trend:
Left to right: More protons (Smaller atomic radius)
-> Stronger nuclear attraction (pull) therefore more energy release.
Down a group: EA decreases, more sheilding = less attraction less energy (Bigger atomic radius)
Smaller atomic radius = more energy release = more EA (opposite)
ELements with 0 electron affinity = Noble gasses and alkalie earth metals.
Is energy released or is energy required? Release = strong attractive forces, required = strong repuslive forces/not looking for an electron)
Electronegativy meaning?
The ability of an atom to attract electrons in a bond
Higher electronegativity = stronger pull
Lower electronegarivity = weaker pull
Electronegativity Trend + Why
Left to right –> Electronegatvitity increases
- More protons, more attraction –> the pull of shared electrons are stronger
Down a group –> Electrongativity decreases
-Increased sized atom = weaker attraction (Less pull on shared electrons)
-More sheilding = weaker attraction (:ess pull on shared electrons)
