ENGN1215 Study Guide - Quiz Guide: Alkaline Earth Metal, Alkali Metal, Bohr Model
Notes from Worksheets
The atom
Bohr model: assumes electrons live in discrete orbitals
Wave mechanical model: electron cloud
Material classification:
• Metal
• Ceramic: metal and non-metal e.g. glass, concrete
• Polymer- plastic
• Composite e.g. wood
• Non-metals
• Semi-conductors
ISOTOPE: two or more atoms of one elements with different atomic masses
Note: atomic mass of an element is the average atomic mass of its naturally
occurring isotopes
PERIODIC TABLE: Alkali metals: group 1, Alkali earth metals: group 2, halogens:
group 3, inert gases: group 8
If d sub shell is incomplete the element is a transition metal
Single s electron- alkali metal
Two s electrons- alkali earth metal
One away from complete p shell- halogen
Bonding:
• Ionic- oppositely charged ions (ceramics)
• Covalent- electron sharing → stable electron configuration (polymers)
• Metallic- ion core, sea of electrons (metals)
• Grain boundary energy is lower than surface energy because there are
less unsatisfied bonds
• Ionic bonded molecules are more likely to form a crystalline structure
(covalent → directional bonding → more difficult to assume positions
giving rise to an ordered structure)
Diffusion:
• Temperature increases → internal energy increases → atoms vibrate
more → diffuse more easily
Equations:
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Document Summary
Bohr model: assumes electrons live in discrete orbitals. Material classification: metal, ceramic: metal and non-metal e. g. glass, concrete, polymer- plastic, composite e. g. wood, non-metals, semi-conductors. Isotope: two or more atoms of one elements with different atomic masses. Note: atomic mass of an element is the average atomic mass of its naturally occurring isotopes. Periodic table: alkali metals: group 1, alkali earth metals: group 2, halogens: group 3, inert gases: group 8. If d sub shell is incomplete the element is a transition metal. Ionic- oppositely charged ions (ceramics: covalent- electron sharing stable electron configuration (polymers, metallic- ion core, sea of electrons (metals, grain boundary energy is lower than surface energy because there are less unsatisfied bonds. Ionic bonded molecules are more likely to form a crystalline structure (covalent directional bonding more difficult to assume positions giving rise to an ordered structure) Diffusion: temperature increases internal energy increases atoms vibrate more diffuse more easily.
