Inside the Atom Periodic Table Covalent Bonding.
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Transcript of Inside the Atom Periodic Table Covalent Bonding.
Inside the AtomPeriodic Table
Covalent Bonding
Electron Shells
• Contain all electrons at approx. same energy and distance out.
Shell Number designation
Electron capacity (2n*n)
1st 1 2
2nd 2 8
3rd 3 18
4th 4 32
5th 5 50
Valence Electrons
Electrons in outer shell– Farthest out– Most loosely held
• Most likely to be involved in a chemical reaction
Periodic Law
• Attributed to Mendeleev – 1869• Similar properties occur @ regular intervals
(periods)• Based on experimental results (laws)• Didn’t know why (theory) until electron orbits
or shells were discovered
Representative Elements
Halogens
Valence Electrons
• Equal to the number of the column for representative elements– So all elements in a column have same # of
valence electrons (representative)– Valence electrons determine chemical
behavior– Example Ca and Sr
Lewis or Electron Dot Structure
• Number of dots = number of valence electrons = number of column.
Octet Rule of Bonding
• All but smallest atoms want to have 8 valence electrons
• Or all atoms want to be like the closest Noble Gas– Lose electrons– Gain electrons– Share electrons – Covalent Bonding
Ionic Bonding
Covalent Bonding
• Sharing electrons instead of transferring – H + H → H H– Cl + Cl → Cl Cl
– H + O + H → H O H or H – O – H
H H – 4H + C → H C H or H – C – H
H H
Nobel gasconfiguration
Water
Covalent Bonding
• Number of bonds an atom wants to form?– Equal to number of electrons it is missing to
be like a noble gas
• How many O’s will react with C ?
• How many F’s will react with N ?
Multiple Covalent Bonds
• Single bond – share one pair of electrons
• Double bond – share two pair
• Triple bond – share three pair
• All but group VIIA and H can double bond
• Group IVA & VA can triple bond– Mostly C, N, Si, P
Naming Binary Covalent Compounds
Naming Binary Covalent Compounds
Shapes of Compounds
• You will get a good feel for shapes in lab 5
H8 – C3
• 16, 18, 19, 21 - 25, 27, 28, 31, 32, 55, 56, 60, 62, 64, 80