Chemistry of Life

What is the distinction between biology and chemistry

there is no clear distinction because the two sciences are parts of the same whole

Which 4 elements make up approximately 96% of living matter

C, H, N, O

carbon, hydrogen, nitrogen, oxygen

give an example of a trace element essential to humans

iodine

example of the following is trace element that is essential to humans & other living organisms

Iron

why is each element unique and different from other elements

atomic number

how do you approximate the mass number of an element

add together the number of protons and neutrons

the atomic number determine the amount of which subatomic particles

protons & electrons

what is an atomic form of an element with the same number of protons but a different number of neutrons

isotope

what makes isotopes differ from eachother

number of neutrons

what happens to electrons if an atom absorbs sufficent energy

the electron may move to an electron shell farther out from the nucleus

what do the reactive properties or chemical behavior of an atom depend on

the number of electrons in the outer valence shell in the atom

describe the characteristics of an atom with eight electrons in its outer electron shell

stable & nonreactive

what is valance

the amount of electrons an atom needs to achieve a stable, filled outer shell

electron configuration

what is a covalent chemical bond

outer-shell electrons are shared by two atoms so as to satisfactorily fill the outer electron shells of both

what do atoms form when they share electron pairs

molecules

what do the four elements most abundant in life have in common

they all have unpaired electrons in their valence shells

what is formed when two equally electronegative atoms interact

ionic bonds

when is a covalent bond likely to be polar

wen one of the atoms sharing electrons is much more electronegative than the other atom

polar vs nonpolar

polar: uneven distribution of charge

nonpolar: even distribution of charge

which of these are a polar covalent bond: C—H or H—O

H-O

When do Van der Waals interactions happen

when electrons are not symmetrically distributed in a molecule

Describe chemical equilibrium

Reactions continue with no effect on the concentrations of reactants and products