1 Atomic Structure

Question 1

valence electrons

Answer 1

outermost shell of electrons –> higher energy

have strongest interactions with surroundings

Question 2

isotopes

Answer 2

varying mass numbers

Question 3

atomic weight

Answer 3

weighted average of different, naturally occurring, isotopes

Question 4

Avogadro’s number

Answer 4

1 mole = number of whatever “things” one is concerned about

= 6.02 x 10^23

Question 5

Planck relation

Answer 5

energy omitted as electromagnetic radiation from matter

comes in discrete bundles called quanta

Question 6

Planck’s equation

Answer 6

E = hf

h = Planck’s constant = 6.626 x 10^(-34) J s

Question 7

Bohr’s model

Answer 7

angular momentum of electrons orbiting hydrogen nucleus

Question 8

Bohr’s equation

Answer 8

L = n h / 2 pi

Question 9

energy of electron orbiting hydrogen nucleus

Answer 9

E = -R(H) / n^2

Question 10

ground state

Answer 10

state of lowest energy of atom
(all electrons in lowest possible orbitals)

all systems tend towards minimal energy)

Question 11

excited state

Answer 11

at least 1 electron moves to subshell of higher than normal energy

Question 12

atomic emission spectra

Answer 12

fingerprints of electron transition

identifies element by line spectra

application of Bohr’s model

Question 13

equation for energy of emitted photon

Answer 13

E = hc / lambda = -R(H) [(1/n(i)^2) - (1/n(f)^2)]

Question 14

atomic absorption spectra

Answer 14

at specific wavelengths
accurate to make electro transition to “excited”
also a fingerprint (element-specific)

required when element is in gas phase

application of Bohr’s model

Question 15

orbitals

Answer 15

electrons move rapidly around nucleus – localized to regions

Question 16

Heisenberg Uncertainty Principle

Answer 16

impossible to determine simultaneously, accurately, both momentum AND position of electron

IF want position, electron must stop (no momentum)
IF want momentum, electron must move (lose position)

Question 17

Pauli Exclusion Principle

Answer 17

no two electrons in a given atom can possess the same 4 quantum numbers

Question 18

principle quantum number (n)

Answer 18

shell

increasing n increases energy level and radius of shell

Question 19

max number of electrons within shell

Answer 19

2n^2

Question 20

azimuthal (angular momentum) quantum number (l)

Answer 20

shape and number of subshells

any value 0 to (n-1)

Question 21

max number of electrons within subshell

Answer 21

4l + 2

Question 22

magnetic quantum number (m(l))

Answer 22

specifies orbital

any value -l to l

Question 23

spin quantum number (m(s))

Answer 23

+(1/2) or -(1/2)

paired spins –> same orbital
parallel spins –> different orbitals

Question 24

Aufbau Principle

Answer 24

building-up principle

each subshell fills completely before electrons begin filling next one

Question 25

Hund’s rule

Answer 25

orbitals filled first with maximum number of parallel spins before paired spins
(electron repulsion)

Question 26

paramagnetic material

Answer 26

atoms with unpaired electrons, will orient spins in alignment with magnetic field

attraction

Question 27

diamagnetic material

Answer 27

atoms with only paired electrons

slightly repelled by magnetic field