GB1: Chapter 2

Question 1

Atomic nucleus

Answer 1

protons and neutrons packed tightly at center of atom, is + charged due to protons

Question 2

common elements of human body

Answer 2

carbon, nitrogen, hydrogen, oxygen, potassium, phosphorus, magnesium, calcium, chlorine, sodium, sulfur

Question 3

compound

Answer 3

2 or more elements combined in fixed ratio

Question 4

electron cloud

Answer 4

electrons rapidly move about the nucleus, forming a cloud of - charge

Question 5

Electron orbitals

Answer 5

3D space where electron is found 90% of the time
No more than 2 electrons occupy single orbital

In 2nd energy shell, 4 orbitals can hold up to 8 electrons (2s & 2p = 8 electron spaces)

Question 6

electron shell

Answer 6

fixed energy shell, electron’s state of potential energy

Question 7

electrons absorb/gain energy:
electrons lose energy:
the amount of energy gained/lost:

Answer 7

increase in energy level (further away from nucleus)

decrease in energy level (closer to nucleus)

equals the amount of energy between shells

Question 8

elements

Answer 8

pure substances, cannot be broken down into other substances

Question 9

energy

Answer 9

capacity to cause change

Question 10

every electron shell has electrons at certain energy level that are distributed among…?

Answer 10

specific number of orbitals of certain size and orientation

Question 11

how does atom stay together?

Answer 11

attraction between the +charged nucleus and -charged electrons

Question 12

in chemical rxns, what is involved?

Answer 12

valence electrons are directly involved, chemical bonds are being broken/formed

Question 13

inert elements

Answer 13

chemically nonreactive elements that have complete valence shell

Question 14

matter

Answer 14

anything that has mass and takes up space, made up of elements

Question 15

molecules

Answer 15

2 or more atoms covalently bonded together

Question 16

potential energy

Answer 16

energy that matter has due to its location or structure, energy locked into structure-not currently changing
matter naturally moves toward the lowest possible state of potential energy (nelsen’s law #2!)

Question 17

subatomic particles

Answer 17

these make up an atom
proton +
neutron no charge
electron -

Question 18

trace elements w/ example

Answer 18

elements required by organisms in minute quantities (less than 0.01% mass) ex: fluorine, boron

Question 19

valence shell, what does it determine?

Answer 19

outermost shell of electron, it determines the chemical behavior of atom

Question 20

atomic number

Answer 20

of protons

of protons = # of electrons in neutral atom

Question 21

Atomic mass (3)

Answer 21

atom’s total mass, weighted average of isotopes, can be estimated by mass number (# protons + # neutrons)

change in proton # = different element
change in neutron # = isotope of element

unit of measurement is DALTONS

Question 22

isotopes

Answer 22

Atoms of element that have different number of neutrons (different atomic masses)

Question 23

radioactive isotopes

Answer 23

nucleus decays spontaneously and gives off particles and energy. unstable, so goes to lowest energy level for stability - nelsen’s law #2!
when this changes the # of protons, atom changes to different element

Parent isotope decays into its daughter isotope at fixed rate

Question 24

radioactive tracers

Answer 24

diagnostic tools in medicine: radioactive isotopes are incorporated into biologically active molecules used as tracers to track atoms during metabolism
also used with sophisticated imaging instruments

Question 25

half-life

Answer 25

time it takes for 50% of parent isotope to decay

Question 26

radiometric dating

Answer 26

process to measure ratio of different isotopes and calculate how many half lives have passed since organism was fossilized/rock was formed

Question 27

chemical bonds w/ 5 types

Answer 27

attraction between atoms with incomplete valence shells through transfer or sharing of electron(s) single, double, triple: increase in bond # = decrease in bond length = more energy in bonds van der waals hydrogen bonds ionic bonds polar covalent bonds nonpolar covalent bonds

Question 28

bonding capacity

Answer 28

atom's valence, maximum # of bonds that atom can form with other atoms to complete octet, corresponds to # of electrons needed to complete valence shell octet

Question 29

covalent bond

Answer 29

the sharing of a pair of electrons between 2 atoms

Question 30

nonpolar covalent bonds

Answer 30

EQUAL sharing of pair of electrons between 2 atoms due to relatively equal values in electronegativity

Question 31

polar covalent bonds

Answer 31

UNEQUAL sharing of pair of electrons between 2 atoms due to large difference in electronegativity, resulting in partial charges (more EN, negative partial charge; less EN, positive partial charge)

Question 32

electronegativity

Answer 32

attraction of particular atom for electron in covalent bond more EN = stronger pull of electrons

Question 33

ionic bonds

Answer 33

bond formation due to ATTRACTION between cation (+charged ion) and anion (-charged ion) because of complete transfer of valence electron(s) from one atom to another (this is due to the extremely great difference in electronegativity) compounds formed: salts, ionic compounds in 3D lattice

Question 34

hydrogen bonds

Answer 34

weaker chemical interaction, hydrogen atom that is covalently bonded to an electronegative atom (giving it partially +charge) is ALSO ATTRACTED to another electronegative atom (with partial -charge) in cells, usually to oxygen or nitrogen

Question 35

chemical behavior of atom

Answer 35

determined by distribution of electrons in shells, especially in outer shell atoms with same number of valence shells exhibit similar chemical behaviors

Question 36

van der waals interactions

Answer 36

weakest interaction; only occurs when atoms and molecules are close together, due to the partially negative positive and negative parts of atom/molecule as electrons aren’t always evenly distributed

Question 37

molecular shape

Answer 37

depends on position of atom's orbitals. size/shape are what determine molecule's function and how they interact with each other

Question 38

hybridization

Answer 38

when atom forms COVALENT BONDS, the orbitals in its valence shell undergo rearrangement 1s + 3p of valence shell in covalent bond = 4 hybrid orbitals in teardrop shapes

Question 39

morphine vs endorphine

Answer 39

have similar effects due to similar molecular structures as they bind to same receptor in brain

Question 40

chemical equilibrium

Answer 40

DYNAMIC EQUILIBRIUM forward/reverse rxns occur at same rate, relative concentrations of reactant/product don't change more reactant-> produce more products More product -> produce more reactants

Question 41

orbitals, electron configuration

Answer 41

electrons occupy opposite regions of atom (because they repel each other) electron spins must be opposite of each other electron configuration shows how electrons are distributed in orbitals

Question 42

reactivity of atom

Answer 42

due to the unpaired electrons in one or more orbitals in valence shell

Question 43

1s___

Answer 43

1s = orbital 1 = energy shell s = determines orbital's shape s = sphere p = propellor

Question 44

chemical reactions

Answer 44

forming/breaking chemical bonds leading to change in composition of matter all are theoretically reversible

Question 45

polar covalent bond value

Answer 45

0.4 < EN < 0.7

Question 46

nonpolar covalent bond value

Answer 46

EN < 0.4

Question 47

ionic bond value

Answer 47

EN > 1.7