Inorganic-Period 3

  • Created by: Hindleyc
  • Created on: 16-06-18 10:47
How are elements classified?
As S,P or D block according to which orbitals the highest energy electrons are in
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What is their position on the periodic table determined by?
Proton number
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What happens to atomic radius as you go across period 3?
Atomic radius decreases because the increased number of protons creates a more positive charge attraction for electrons which are in the same shell with similar shielding
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What is the general trend for ionisation energy across period 3?
Increase due to increasing number of protons as electrons are being added to same shell so more energy required to remove the outermost electron
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Why is there a small drop between Mg and Al?
Mg has its outer electrons in the 3s subshell whereas Al is starting to fill the 3p subshell so Al's electron is slightly easier to remove because the 3p electrons are in higher energy so lower I.E
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Why is there a small drop between phosphorus and sulphur?
Sulphurs outer electron is being paired up with another electron in the same 3p orbital. When the second e- is added to the orbital there is slight repulsion between the 2 negative charged e-'s which makes the second e- easier to remove lowering I.E
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What is this trend the same as?
Period 2 with drops between Be and B and N and O for same reasons except different numbers i.e 2s not 3s
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What bonding does Na,Mg and Al have? what does this do across the period?
Metallic bonding- increases across the period because there are an increased number of electrons in outer shell that are released into sea of delocalised electrons. Inc +ve charge, inc no delocalised e- and dec radius
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What happens as strength of metallic bond increases?
More energy is needed to break the stronger metallic bonds so mp and bp higher
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What 2 factors affect metallic bonding?
Charge density- ratio of ions charge to its size-Na large w/ small charge but Al3+ ions smaller with larger charge (3e-) so higher charge density-more strongly attracted to delocalised e- so stronger metallic bond. Number of free e- inc nuclear charg
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What the 2nd factor
Number of free e- - inc nuclear charge and increased number of delocalised electrons
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Why does Si have a high mp and bp?
Macromolecular- many strong covalent bonds between atoms as each atom is bonded covalently to 4 other Si atoms creating tetrahedral structure needing lots of energy to break covalent bonds therefore High mp and bp
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What are P4 S8 &Cl2? what do they have b/w them? What is p4? S8? Cl2?
Simple molecular- only weak van Der Waals forces b/w molecules so little energy needed to break them therefor slow mp and bp. P4=tetrahedral, s8=crown shaped large so inc SA so more v.d.w and high mp&bp (more e-). Cl2=diatomic
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What is Ar?
Monoatomic-individual atoms with extremely weak v.d.w
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What is overcome when you boil/metl?
V.D.W (so SA) not covalent
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Whta is this similar to?
Period 2
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Overall summary, across period?- A.R, I.E, MP
decrease, Increase decrease increase decrease then increase, inc dec Inc then dec
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Card 2

Front

What is their position on the periodic table determined by?

Back

Proton number

Card 3

Front

What happens to atomic radius as you go across period 3?

Back

Preview of the front of card 3

Card 4

Front

What is the general trend for ionisation energy across period 3?

Back

Preview of the front of card 4

Card 5

Front

Why is there a small drop between Mg and Al?

Back

Preview of the front of card 5
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