Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chapter 2A: Chemistry of Life - Coggle Diagram
Chapter 2A: Chemistry of Life
ATOMS AND MOLECULES
Atom: positively charged PROTONS + neutral NEUTRONS in the NUCLEUS, negative ELECTRONS moving AROUND the nucleus in orbitals
PERIODIC TABLE, theory of molecular orbitals give info about specific atoms
ATOMIC NUMBER: number of PROTONS
atoms in COLUMNS share features
Specific atoms can have DIFFERENT NUMBER of neutrons, affects overall STABILITY
orbitals are MOST STABLE when occupied by specific number of electrons (GOING DOWN NOBLE GASES COLUMN)
first orbital = 2
next orbital 10
next orbital 18
every orbital after ADD 18
MOST STABLE when ALL orbital sets are filled
example: Carbon has 6 protons and 6 electrons, MISSING 4 ELECTRONS to be most stable at 10
Orbital sets can be filled by SHARING electrons between atoms
COVALENT BOND: shared electrons (stronger, STABILIZES the atoms in molecules)
ABILITY of atoms to combine with other atoms is determined by VALENCE ELECTRONS (electrons in the outermost orbitals, have the highest energy level of the atom)
merged orbital is called a MOLECULAR ORBITAL
1 more item...
IONS
IONS: specific atoms and molecules can also have DIFFERENT NUMBER OF ELECTRONS
TYPES
ANION: more electrons than protons (NEGATIVE)
CATION: more protons than electrons (POSITIVE CHARGE)
Ions can form NON-COVALENT BONDS (IONIC BONDS)
strong AWAY from water
weak AROUND water
WATER
Water is POLAR: shared electrons are distributed asymmetrically between oxygen and hydrogen atoms
polar: UNEVEN sharing of electrons between 2 atoms
WHY? ELECTRON NEGATIVITY: difference in the ability of the atoms to attract electrons
electronegativity INCREASES across a row in the periodic table because as the number of PROTONS increases, ELECTRONS are held MORE TIGHTLY to the nucleus
WATER: oxygen has HIGHER tendency to attract electron pairs than hydrogen, electrons are more localized in the OXYGEN side of H2O
non-polar: EVEN sharing
water molecules make HYDROGEN BONDS: interaction between slightly positive hydrogen and an electronegative atom
for hydrogen bonds, angle and distance is crucial (WIGGLING makes them loose)
in LIQUID phase: wiggling just right to keep MAKING and BREAKING the hydrogen bonds (CONTINUOUSLY BONDING AND RELEASING)
molecules are packed MORE CLOSELY (WHY LIQUID IS DENSER THAN ICE)
SOLID state: water molecules bond in a RIGID configuration and hydrogen bonds KEEP water molecules FARTHER apart (SOLID IS LESS DENSE THAN LIQUID)
water molecules bond to FOUR other water molecules to form an open crystalline structure
GAS state: water molecules move TOO QUICKLY to bond
Other POLAR and CHARGED substances move FREELY into and in water: because polar molecules interact with other polar molecules
HYDROPHILIC: water loving
ex. sugars, salts, proteins
NON-POLAR substances crowd AWAY from water
HYDROPHOBIC: water-fearing
ex. oils, fats, lipids
Features of water are explained by HYDROGEN BONDS
HIGH COHESION: water molecules are able to STICK TOGETHER
contributes to UPWARD WATER MOVEMENT IN PLANTS
HIGH SURFACE TENSION: hydrogen bonding creates a THIN film on water surface, enough resistance for super light insects to walk on it but NOT humans because hydrogen bonds are TOO WEAK
RESISTANCE TO RAPID TEMPERATURE CHANGE
an increase in the constant motion of molecules increases the temperature
when water is heated, heat breaks the hydrogen bonds between molecules
temperature increases SLOWER
Water can IONIZE (proton, hydroxide)
Sometimes the O-H covalent bond in a single water molecule breaks INSTEAD OF the hydrogen bond between the 2 water molecules
pH of an aqueous solution is a measure of the acidity (concentration of protons) of the solution
measurement of relative ratio of H+ TO OH-
ACIDIC (LESS THAN 7.0): more H+
BASIC ALKALINE (MORE THAN 7.0) : more OH-
generates
H+ (proton): AN ACID
OH- (hydroxide): A BASE