Atomic structure Flashcards
Define atom
The smallest part of an element which can not be further broken down by chemical means
What do the below letter denote?
A - n
- X
Z
A - Mass number (protons + neutrons)
Z - Atomic number (protons)
X- Element
n - charge
Define isotope
Atoms of the same elements with different number of neutrons in the nucleus
Calculate the Ar of chlorine where Cl-35 is abundant as 75% and Cl-37 is abundant in 25%
[ (0.75 x 35 ) + (0.25 x 37) ] =35.5 g/mol
Uses of Radioactive isotopes
Nuclear power generation
Sterilisation of surgical instruments
Finding cracks and and stresses in metal
Carbon dating with carbon -14
Radiotherapy with Co-60
Tracers in medicine with. I-125 and I-131
Formula for velocity of a wave with units
c = v x y
c - m/s velocity
y - m wavelength
v -1/s frequency
The order of the electromagnetic spectrum
Radio waves, Micro waves, Infrared, Visible light, Ultraviolet light, X-rays, Gamma radiation
How does frequency, wave length and velocity change with the electromagnetic spectrum
Radio waves, Micro waves, Infrared, Visible light, Ultraviolet light, X-rays, Gamma radiation
Velocity is constant
Wavelength decreases from Radio to Gamma
Frequency increases from radio to gamma
Which has a longer wave length, red or violet light?
Red light
Which has a higher frequency, red or violet. light?
Violet light
How can light be used to determine an element?
Each element has its own characteristic line spectrum as they have non continuous emission spectra
Order of filling electron orbitals
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
Electron configuration of Cu and Cr
Cu - [Ar] 4s1 3d5
Cr - [Ar]. 4s1 3d10
Electron configuration of Cu+
Cu + = [Ar} 3d10
When considering a transition element in the first row, from which orbital are electrons removed first
First 4s electrons are removed and then 3d electrons
What is the shape of an S and P orbital
S - Spherical
P - Orthogonal
Define first ionization energy of an element
The energy required to remove one mole of electrons from an atom in its gaseous state measure in kJ/mol
Formula for energy required to remove one electron and one mole of electrons
E = hv = hc/y
c - the speed of light
y - wave length
v - frequency
h- planks constant 6.63 x 10^-34 J s
For one mole of electrons simply multiply by 6.02 x 10^23
Explain emission and absrobtion spectra
As energy is supplied to an electron it reaches an excited state, and absorbs the photons of a specific wave length. This produces the black bands in absorption spectrum
As the electrons fall from sub levels they release energy in the form of photons producing the coloured lines in emission spectra
The larger the fall the more energy released thus when an electron falls to
n=1 ultra voilet is released
n=2 visible light is released
n=3 infrared is released
Describe the hydrogen emission spectra
A series of lines only certain frequencies/wavelengths that show convergence at higher frequency/energy
