| A | B |
|---|
| CHNOPS | 97% of mass of organisms made of these elements |
| trace elements | 3% of mass of organisms made of these elements (Ca, K, Na, Cl, Fe, Mg, Zn) |
| Carbon (C) | the hub element of organic compounds |
| four | # valence electrons & # covalent bonds formed by C atoms |
| covalent bond | chemical bond type made when nonmetal atoms share electrons |
| ionic bond | chemical bonds formed when metal atoms lose electrons, giving them to nonmetal atoms that take the electrons |
| Oxygen, nitrogen | two electron greedy members of CHNOPS having high electronegativity |
| Carbon, Hydrogen, phosphorous, Sulfur | four members of CHNOPS having LOW electronegativity (electron generous) |
| polar covalent bond | like C-O or N-O or O-H, covalent bonds of electron greedy & electron generous atoms |
| nonpolar covalent bond | covalent bonds between atoms having similar electronegativity (both low OR both high) |
| partial positive charge | the charge on the lower electronegativity atom in a polar covalent bond ( like C in C-O) |
| partial negative charge | the charge on the Higher electronegativity atom in a polar covalent bond ( like O in C-O) |
| Carbon backbone | chain of covalently bonded C's in organic compounds |
| single covalent bond | symbol -, one pair shared valence electrons |
| double covalent bond | symbol =, two pairs shared valence electrons |
| organic molecules | Covalently bonded molecules containing C & H & sometimes other members CHNOPS |
| iron (Fe) | trace element carrying Oxygen in blood |
| Calcium(Ca) | Trace element found in bone minerals |
| K, Na, Cl | trace elements used in nerve cell electrical signals |
| water | inorganic compound comprising more than half of an organism's mass |
