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6 Cards in this Set
- Front
- Back
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Essential elements of life ? |
The weight of most organisms is constituted of
96% CARBON , OXYGEN , NITROGEN and HYDROGEN.
4% PHOSPHORUS, SULPHUR,CALCIUM,and POTASSIUM.
Trace elements :- Fe, I , Co, Cu, Zn and Mg |
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Covalent bonds |
Bond that shares a pair of valence electrons |
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Non - covalent :- ionic or electrostatic |
• exist as dissociated ions with valence shells full. • strongest among non-covalent |
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Ions that are essential in ALL species |
Ca , K , Na , Mg and Cl- |
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Hydrogen bonds |
An electrostatic attraction between 2 POLAR groups that occurs when a H atom covalent lyrics bond to a highly electronegative atom •strongest •structure stability can be broken. |
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Van deer Waal bonds |
Attraction between NON - POLAR molecules • weak •occurs when molecules are very close • electron hot spots 》transient dipoles |
