Lecture 2: Basic Chem & water Flashcards
valence electrons
outer electrons in a shell
valence shell
outermost electron shell
covalent bonds
sharing of a pair of valence electrons
electronegativity
the attractive force that an atomic nucleus exerts on electrons in a chemical bond
which of 6 main elements has highest electronegativity?
Oxygen
non-polar covalent bond
covalent bond between two atoms of the same element
electronegativity
polar covalent bond
when an atom is bonded with another atom with higher electronegativity
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ions
oppositely charged atoms
cation
positively charged ion
anion
negatively charged ion
ionic bond
attraction between cation and anion
ionic compounds (salts)
compounds formed by ionic bonds
hydrogen bond
a weak attraction between a partial positive H atom and partial negative O or N atom
how many hydrogen bonds are in a single molecule of water?
none
where do hydrogen bonds form?
between water molecules or between partial positive H atoms and partial negative O or N atoms
high heat capacity of water
water resistant to temperature change due to hydrogen bonds
high heat vaporization of water
water resistant to evaporation due to hydrogen bonds
cohesion
water sticks to itself due to hydrogen bonds
adhesion
water sticks to other water molecules due to hydrogen bonds
hydrophilic
to be attracted to water (polar molecules)
hydrophobic
to repel water (non polar molecules)
acids
INCREASE proportion of H+ to OH- in a solution
bases
REDUCE proportion of H+ to OH- in a solution
macromolecules
polymers made of monomers
condensation (dehydration)
removal of water to link monomers togerther
hydrolysis
addition of water to break up a polymer into monomers
