Radiation - Unit One Flashcards
What is electromagnetic radiation?
Waves that travel in a vacuum at 3X10^8 m/s
Explain how electromagnetic radiation has dual nature.
It can behave as both a stream of particles (when absorbed by matter) as well as waves.
What kind of radiation is at the high energy end of the spectrum?
Short wavelength, high frequency
What kind of radiation is at the low energy end of the spectrum?
Long wavelength, low frequency
Explain atomic emission spectra
1) gaseous element is excited using electricity, promoting electrons to higher energy levels
2) electrons fall from the higher levels emiting energy in the form of light
3) electrons that make a big transition have high energy, high frequency and low wavelength, for small transitions vice versa
4) different wavelengths of light given off pass into a prism where they’re refracted (shortest refracted most)
5) LINE spectrum shows the existence of fixed energy levels in atoms
Name the different series relating to EM
Name of series - Lyman, Balmer, Paschen
Energy level EXCITED electron falls to - 1, 2, 3
Part of spectrum found - UV, visible, infrared
Explain atomic emission spectra
Hydrogen and helium makes up the Sun which Is known because a spectroscope was pointed at the sun and an emission spectrum matching hydrogen and helium was produced
What is an atomic orbital?
An area where the probability of finding an electron is high
What does n stand for (atomic orbitals)?
Principal quantum number, related to size or energy of the orbital (number of shells)
What does l stand for (atomic orbitals)?
Angular quantum number, l(n-1)
If n = 2
L = 0,1
What do values of l correspond to (atomic orbitals)?
0 - s
1 - p
2 - d
3 - f
Draw an s orbital
Spherical
Draw a p orbital
Figure of 8
Z (upright)
X (45 degrees right)
Y (135 degrees right)
What does m stand for (atomic orbitals)?
Shows multiplicity and orientation
What does s stand for (atomic orbital)
Spin quantum number +/- 1/2
What does the pauli exclusion principle state?
No two electrons can have the same set of four quantum numbers. So the number of electrons in an orbital can’t exceed 2 and they must have opposite spins.
What does Hunds rule state?
Electrons fill degenerate orbitals singly, keeping spins parallel before pairing.
What does the Aufbau principle state?
Electrons fill the lowest energy orbitals first.
What are degenerate orbitals?
Orbitals of equal energy (4S fills before 3D)
Why does first ionisation energy increase across a period?
The number of positively charged protons in the nucleus increases exerting a stronger pull on the electrons
Where are s p d and f areas on the periodic table?
S Block is on the left
D is in the middle
P is on the right
F is on the bottom
What has two electron pairs?
Linear
