Class 2 How Atoms combine with similar and dissimilar atoms
Periodic table Electron configurations Energies Bond types Bond
types and properties. Fall 12
Slide 2
Columns represent groups of similar properties, Group 1A,
alkali metals; 8, inert gases; 7B halides
Slide 3
Atomic Model Nucleus Protons +ve charge Neutrons no charge
Orbitals Electrons ve charge Atoms protons and electrons balance
each other, so no net charge. Ions Positive or negative charge
imbalance Na + or Cl - Quantum mechanical model Replaced this
one
Slide 4
Electron States Each Quantum Number Fills up first- 1, 2,
3,4,5,6 etc Chlorine atom, z=17, 1s 2,2s 2,2p 6,3s 2,3p 5,
electrons = 2+2+6+2+5=17 So 1S 2,then 2S 2,2p 6, then 3S 2,3P 6,3D
10,then 4S etc there are some Discrepancies though.
Slide 5
Note 4s before 3d Note 4s1 3d5 Note 4s1 3d10
Slide 6
Electron Filling of Orbitals 1s 2s 2p 3s 3p 3d 4s 4p 4d Z =46
1s 2s 2p 3s 3p 3d 4s 4p36 1s 2s 2p 3s 3p 3d 4s30 1s 2s 2p 3s 3p
4s20 1s 2s 2p 3s12 1s 2s 2p10 1s 2s4 1s2 On Ionisation, 4s levels
empties first.
Slide 7
Filling of Shells Electrons shells like to be full, half full
or empty. Full shells inert status, for example helium Full or
empty, between elements by ionic or covalent bonding. Metallic
bonding sharing of electrons.
Slide 8
Periodic Table Rows number of shells 1,2,3,4 etc Column number
of electrons in outer shell Columns have like properties as number
of electrons in outer shell same. Atomic number number of electrons
and so protons in atom. Different number of electrons changes
properties and produces elements
Slide 9
Bonding Types Between like atoms metallic or covalent Between
different atoms metallic, ionic or covalent. Primary ionic,
covalent and metallic. strong Secondary hydrogen, van der Waals.
weak.
Slide 10
Ionisation energies for the hydrogen atom 4s level just below
3d
Slide 11
Ionic Bonding Na, z=11, # of electrons and protons,
1s2,2s2,2p6,3s1 : 2+2+6+1=11 Note 3s1, lose this electron, full
orbitals then ; alkali metals Cl, z=17, 1s2,2s2,2p6,3s2,3p5 :
2+2+6+2+5=17 Note 3p5, gain one electron, full 3p6 orbital, halide
ions Na+ ion due to loosing one electron, Cl- due to gaining an
electron Ionic bonding between elements with different
electronegativities. Elements on right of periodic table highly
electronegative, and want to Gain electrons, elements on left
electropositive, lose an electron. Directional so brittle type
materials. Ordered structure, move one ion Lose order.Crystalline
structure from this bonding.
Slide 12
Covalent Bonding Hydrogen 1s1, Carbon 1s2,2s2,2p2, so if
hydrogen can share one electron And carbon can share four
electrons, both elements will have full orbitals. Four hydrogens
share with one carbon in covalent bonds. Molecule of methane gas
formed different elements or same can exhibit Covalent bonds eg
carbon.Elements with half full outer orbital.Can be
crystalline
Slide 13
Metallic Bonding Electrons shared in a gas cloud as outer
orbitals not filled. Lots of empty energy states, such as 3d etc.
Can be single element, eg gold, or mixtures such as brass, or
aluminum alloys. No directionality to bonds, so ductile and
conductive. Crystalline usually, but not ordered. Ion cores protons
And neutrons
Slide 14
Metallic Conductivity Electrons inElectrons out Metals are
conductive as the electrons are not specific to an ion Applications
electrical wire, copper circuit boards, thermocouples.
Slide 15
Bond Energy and Properties State 25 C Solid Solids Liquid Solid
Gases Bond energy controls melting point. Primary Secondary
Slide 16
Secondary Bonding Hydrogen needs presence of hydrogen, single
electron effect, non crystalline normally Van Der Waals dipole type
bonding, due to slight charge imbalance with distance. Non
crystalline normally.
Slide 17
Secondary Bonding Positive charge here as electron Favors
carbon side Water good example of hydrogen bond Between hydrogen
and oxygen covalent Between molecules, hydrogen bond.
Slide 18
Homework How does calcium and flourine bond to each other? How
does aluminum bond to other aluminum atoms and how does silicon
bond to other silicon atoms? Why are metals conductive?
