Periodicity Flashcards
Original Periodic Table
Created by Demitri Mendeleev (Russian scientist)
Arranged by increasing atomic mass (small –> big)
Empty gaps were left for elements he predicted by hadn’t been discovered yet
Modern Periodic Table
Arranged by atomic number (small –> big)
Periodic repetition of chemical and physical properties
Periods and Groups
Periods (rows) go left to right, there are 7 rows
Periods indicate the number of energy levels
Groups (columns) go top to bottom, there are 18 columns
8 groups are known as Families
Families share chemical and physical properties
Group 1A (Alkali Metals)
1 valence electron
Hydrogen is NOT part of this family
Never found in a free state (always paired with something else)
Most reactive group of metals
Li Na K Rb Cs Fr
<———————————————–>
Least reactive Most reactive
Lewis Dot Diagram
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X
Group 2A (Alkaline Earth Metals)
2 valence electrons
2nd most reactive group of metals
Never in a free state
Be Mg Ca Sr Ba Ra
<—————————————————>
Least reactive Most reactive
Lewis Dot Diagram
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X
Group 3A (Boron Family)
3 valence electrons
3rd most reactive group of metals
Never in a free state
B Al Ga In Ti
<————————————->
Least reactive Most reactive
Lewis Dot Diagram
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X .
Group 4A (Carbon Family)
4 valence electrons
Not very reactive
Contains metals, metalloids, and nonmetals
C Si Ge Sn Pb
<—————————————>
Not metal Metal
Lewis Dot Diagram
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X .
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Group 5A (Nitrogen Family)
5 valence electrons
Not very reactive
First group of mostly non-metals (first to contain gas)
N P As Sb Bi
Lewis Dot Diagram
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. X .
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Group 6A (Oxygen Family)
6 valence electrons
Reactive non-metals (O, and S)
O S Se Te Po
Lewis Dot Diagram
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. X . .
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Group 7A (Halogens)
7 valence electrons
Most reactive group of non-metals
Never found in a free state
Poisonous to ALL life
F Cl Br I At
Lewis Dot Diagram
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. X . .
. .
Group 8A (Noble Gasses)
AKA inert gasses
8 valence electrons (except for He)
Complete outer shells
Most non-reactive family
Does not react naturally with anything
He Ne Ar Kr Xe Rn
Lewis Dot Diagram
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. . X . .
. .
Transition Metals
Not a family/group
D block
Found in a free state
Valence and charges vary
Valence electrons vary
Inner Transition Metals
Not a family/group
F block (Lanthanide series #58-70, Actinide series #90-102)
Mostly man made elements
Valence electrons vary
What about Hydrogen?
Can gain AND loose it’s 1 valence electron
Not in a family
Very flammable
Diatomic (can react with itself, H2)
Metallic Character (periodic trends)
Having qualities of a metal
The further right you go on a periodic table the less metal like an element is
The further down the more an element becomes metallic (metal like)
Size of Atom (periodic trends)
Atomic radius = size of the atom
Distance between two nuclei divided by two
More shells / further down in the periodic table the larger the atom
As you go across (left -> right) the size shrinks (same amount of shells just closer together)
More attraction in the atom the further right on the periodic table
The closer to Cs, the larger the atom
Shielding Effect (periodic trends)
Blocking the protons pull on valence electrons by energy levels between them
More shielding effect —> weaker pull
Effective Nuclear Charge, Zeff (periodic trends)
Protons in the nucleus pulling on the valence electrons
More shields —-> weaker pull
Shielding effect is constant
Further right the more positive/excited the nucleus is
Ionization Energy (periodic trends)
The amount of energy needed to REMOVE an electron
The further right the smaller in size and the stronger the Zeff
Further down the larger in size and weaker the Zeff
Further right the higher the ionization energy
Further down the lower the ionization energy
Stability of Subshells (periodic trends)
The further right on the periodic table you go the more energy it takes to remove, and the more stable the atom
The further left on the periodic table you go the less energy it takes to remove, and the less stable the atom
Electronegativity / Electron Affinity (periodic trends)
The atoms want for an additional electron
The further right the higher the want for an electron
Caused by the octet rule
The higher the Zeff the higher the want for an electron
Noble gasses DO NOT want any electrons (no affinity)
The greater the shells the weaker the affinity
Activity of Metals (periodic trends)
A metal being VERY reactive (Alkali Metals)
Metals want to lose electrons to achieve octet
Metals have a low Zeff
Metals have low ionization energy
Metals have high electron shielding
Cs = Most reactive of all metals
The further right the least reactive a metal is
The further down the more reactive a metals is
Activity of Non-metals (periodic trends)
A non-metal being VERY reactive (Halogens)
Non-metals want to gain electrons to achieve octet
Strong Zeff
High ionization energy
High electron affinity
F = Most reactive halogen
The further right the more reactive a non-metal is
The further down the less reactive a non-metal is
Cations
Cations are smaller than the parent ion
Anions
Anions are larger than the parent ion
