CHEM Ch 9
Terms
undefined, object
copy deck
- explain how electrons exist in atoms and how those electrons affect the chemical and physical properties of elements
- Bohr model and quantum mechanical model
- foundation of modern chemistry
- quantum-mechanical model
-
(def)
a type of energy that travels through space at a constant speed of 3.0 x 10^8 m/s - electromagnetic radiation
-
(def)
characterizes waves; the distance between adjacent wave crests - wavelength
-
(def)
characterizes light waves; the number of cycles of crests that pass through a stationary point in one second - frequency
- wavelength and frequency are...
- inversely related
-
(def)
a particle of light - photon
- the shorter the wavelength...
- the greater the energy
- the wavelength of electromagnetic radiation determines...
- the amount of energy carried by one of its photons
-
(def)
all wavelengths of electromagnetic radiation - electromagnetic spectrum
- radiation on the right:
- short wavelength, high frequency
- radiation on the left:
- long wavelength, low frequency
-
(def)
gamma rays: -
1. shortest wavelength
2. produced by sun, stars, and certain unstable nuclei on earth
3. can damage biological molecules - x-rays:
-
1. longer wavelength than gamma rays
2. can damage biological molecules - UV light
-
1. sunlight
2. can damage biological molecules but not as dangerous - visible light
-
1. longer wavelength than UV light
2. do not cause damage to biological molecules but are bad for eyes - infrared light
-
1. longer wavelength than visible light
2. heat you feel near a hot object
3. night vision - microwaves
-
1. longer wavelength than infrared light
2. used for radar and microwave ovens
3. absorbed by water
4. can heat substances that contain water - radio waves:
-
1. longest wavelength
2. transmits signals for radio, phones, etc. -
(def)
light waves separated in constituent wavelengths - emission spectrum
-
(def)
energy of each orbit - quantum number
-
(def)
fixed - quantized
-
(def)
precise amount of energy in a photon of light - quantum
- as long as an electron remains in a given orbit...
- it does not absorb or emit light and its energy remains fixed and constant
- electrons exist in quantized orbits...
- at specific, fixed energies and specific fixed distances from the nucleus
- when energy is put into an atom...
- elements are excited to higher-energy orbits
- when electrons fall from higher-energy orbits to lower energy orbits atoms...
- emit light
- the energy of the emitted light corresponds to...
- the difference in energy between 2 orbits in the transition
- in the quantum-mechanical atom, orbits are replaced with:
- orbitals
-
(def)
statistical distribution of where an electron is likely to be found - orbitals
- electrons do not behave...
- like particles flying through space
-
(def)
sometimes act electrons act as particles and other times as waves - wave particle duality
- quantum-mechanical model has...
- different orbitals with different shapes
- specify an orbital:
- a number and a letter
-
(def)
determine the energy of the hydrogen quantum-mechanical orbitals - principal quantum number
-
(def)
levels of orbitals - principle shell
-
(def)
indicated by letters in principal quantum numbers - subshells
- subshell letters
-
s
p
d
f - orbitals can also be represented as...
- geometric shapes that encompass most of the volume where the electron is likely to be found
-
(def)
lowest energy state - ground state
- the number of subshells in a given principal shell is qual to...
- the value of n
-
(def)
higher energy level; unstable; emits energy in form of light - excited state
-
(def)
how electrons occupy orbitals - electron configurations
-
(def)
gives similar info but shows the electrons as arrows in a box representing the orbital - orbital diagram
-
(def)
fundamental property of electrons; arrows - electron spin
-
(def)
electrons found in the outermost principle shell with highest quantum number - valence electrons
-
(def)
every other type of electron not found in outermost shell - core electrons
- first 2 columns
- s block
- last 6 columns
- p block
- transition metals
- d block
- inner transition metals
- f block
- the transition series represents the...
- filling of the core orbitals and the number of valence electrons is mostly constant
- the inner electron configuration for any element is:
-
the electron configuration of the noble gas that immediately precedes that element in the periodic table
[noble gas in brackets] - the highest principal quantum number is equal to:
- the row of the element in the periodic table
- the chemical properties of elements are:
- largely determined by the number of valence electrons they contain
- same number of valence electrons =
- similar properties
-
(def)
determined by how far the outermost electrons are from the nucleus - atomic size
- the increase in number of protons results in...
- a greater pull on the electrons, causing atomic size to actually decrease
- as you move to the right across a period...
- atomic size decreases
- the outermost orbitals are farther from the nucleus as
- you move down a column
- as you move down a column,
- atomic size increases
-
(def)
the energy required to remove an electron from the atom in the gaseous state - ionization energy
- ionization energy is
- consistent with the trends in atomic size
- opposite from atomic number and ionization energy
- metallic characters