7.2 Atomic Spectra

Question 1

line spectrum

Answer 1

a series of fine lines at specific frequencies seperated by black spaces

Question 2

Postulates of the Bohr Model (3)

Answer 2

1. the H atom has only certain energy levels (stationary states)
2. the atom does NOT radiate energy while in one of its stationary states
3. the atom changes to another stationary state (electron moves to another orbit) only by absorbing or emitting a photon

Question 3

Bohr Model equation

Answer 3

Ephoton = Eatom = Efinal - Einitial = hv

Question 4

equation for calculating the energy levels of an atom

Answer 4

E = -2.18x10^-18 J (Z^2/n^2)
*Z = charge of the nucleus

Question 5

Equation to find the difference in energy between two levels

Answer 5

ΔE = Efinal - Einitial = -2.18^-18 J (1/nfinal^2 - 1/ninitial^2)
* when the atom emits energy, (nfinal ninitial), so ΔE is POSITIVE

Question 6

ionization energy of hydrogen

Answer 6

the energy required to form 1 mol of gaseous H+ ions from 1 mol of gaseous H atoms = 1.31x10^3 kJ/mol

Question 7

Equation to find the WAVELENGTH of a spectral line

Answer 7

ΔE = hv = hc/λ or λ = hc/ΔE

Question 8

spectrometry

Answer 8

refer to a large group of instrumental techniques that obtain spectra that correspond to a substances atomic or molecular energy levels (emission and absorption spectra)

Question 9

emission spectrum

Answer 9

produced when atoms in an excited state emit photns characteristic of the element as they return to lower energy states

Question 10

absorption spectrum

Answer 10

produced when atoms absorb photons of certain wavelengths and become excited from lower to higher energy states