1: Atomic Structure

Question 1

atomic number (Z)

Answer 1

of protons

Question 2

atomic mass / mass #

Answer 2

of protons + neutrons (in amu)

Question 3

atomic weight

Answer 3

weighted average of isotopes

Question 4

Plank’s quantum theory

Answer 4

energy emitted as EM radiation from matter exists in discrete bundles called quanta (E=hf)

Question 5

Bohr’s model of a hydrogen atom

Answer 5

possible values for the angular momentum of an electron orbiting a hydrogen nucleus depends on n (principle quantum number)

• angular momentum of an electron changes only in discrete amouns with respect to n

Question 6

Energy of the electron

Answer 6

E is directly proportional to n

E=-RH/n^2

• energy of electron changes in discrete amounts with respect to the quantum number
  
  • energy increases the farther out from the nucleus is

Question 7

applications of Bohr model

Answer 7

as electrons go from lower energy to hgiher energy level, they get AHED:

• Abosrb light
• Higher potential
• Exctied
• Distant

Question 8

Atomic emission spectra

Answer 8

electrons in an atom can be excited to different energy levels… but when electrons return to their ground states, they emit a photon with a wavelength characteristic of the specific energy transition it undergoes

E=hc/wavelength

Question 9

Lyman series

Answer 9

group of hydrogen emission lines corresponding to transitions betwen upper levels n>1 to n=1

• larger energy transitions so shorter photon wavelenghts in the UV region of the EM spectrum

Question 10

Balmer series

Answer 10

group of hydrogen emission lines corresponding to transitions from energy levels n>2 to n=2

Question 11

Paschen series

Answer 11

transitions from n>3 to n=3

• smaller energy transition so longer photon wavelenghts in the visible region

Question 12

Atomic Absorption Spectra

Answer 12

when an electron is excited to a higher energy level, it absorbs exactly the right amount of energy to make that transition

Question 13

Heisenberg uncertainty principle

Answer 13

it is impossible to simultaneously determine, with perfect accuracy, the momentum and position of an electron

Question 14

principle quantum number (n)

Answer 14

shell

• the larger the integer of n, the higher the energy level and radius of the electron’s shell
• max # of electrons within a shell 2n^2

Question 15

angular momentum quantum number (l)

Answer 15

refers to the shape and number of subshells within a given pricnipal energy level

• l=0 to n-1
• s: l=0
• p: l=1
• d: l=2
• f: l=3
• max # electrons within a subshell=4l+2

Question 16

magnetic quantum number (m_l)

Answer 16

specifies particular orbital within a subshell where an electron is most likely to be found at a given moment in time

• m_l is an integer between -l and l
  *

Question 17

spin quantum (m_s)

Answer 17

spin orientation

• +1/2 or -1/2

Question 18

n+l rule

Answer 18

the lower the values for the first 2 quantum numbers (n+l), the lower the energy of the subshell

Question 19

anions & cations

Answer 19

anions fill the same way, but for cations start with neutral atom and remove elctrons from the subshells with the highest value for n first

Question 20

Hund’s rule

Answer 20

within orbitals, parallel spins filled first… half-filled and fully-filled orbitals have lower energy energies (higher stability)… 2 exceptions:

• Chromium: [Ar]4s¹3d⁵ rather than [Ar]4s²3d⁴ because of stability
• Copper: [Ar]4s¹3d¹⁰ rather than [Ar]4s²3d⁹ because of stability

Question 21

paramagnetic

Answer 21

unapired electrons… magnetic attraction

Question 22

diamagnetic

Answer 22

only paired electrons so slightly repelled by a magnetic field