Chapter 3: Electronic Structure Flashcards
What is electromagnetic spectrum
All the wavelengths of radiation in different forms of different energy energy
All waves travel at the same speed. How can they be distinguished
Wavelength
What is frequency
No of waves passing a point per second
Relate frequency and wavelength and energy
Shorter the wavelength the more the frequency and hence the more the energy
State wave equation
c=√f
velocity=wavelength×frequency
How do w, f and e vary with the spectrum
Decreasing from radio waves to gamma waves
Energy/freqeuncy increasing from radio to gamma
How is white light split into an atomic emmision spectrum
Wavelengths/frequencies are divided into colors by diffraction through a prism
What is line spectrum
White light split into different wavelengths/frequencies consisting of discrete lines
What happens when atoms are supplied with energy
Electrons gain energy move from lower(ground) to higher(excited state) energy levels
What happens as electrons gradually lose energy
Move from higher to lower energy levels and emit energy of particular wavelength
What prevents electrons from leaving the atom
Electrostatic force of attraction between oppositepy charged protons in nucleus and electrons in orbits
Why are neutrally charged neutrons important
Stability of elements with more than 1 proton, which would repel and nucleus falls apart
State the essentials of Bohr’s model
Electrons move in shells
For any atom there’s a fixed set of allowable orbits/stationary states
As long as electrons remain in their energy levels their energy is constant
An electron can only pass from one stationary state to another giving out/absorbing discrete/definite quantities of energy (quanta)
An electron moves up a level when energy is absorbed. Why does it eventually fall back and what is released
The excited electron is unstable
Electromagnetic radiation/packet of energy/photon
Photons of UV have more energy than of IR
Energy of photon emitted is =
Energy change in atom
Explain in depth the Planck equation (evidence of bohrs model)
Atoms emit photons of certain energies which give likes of certain frequencies as they can only occupy certain orbits
They can either be at this orbit or the other not in between meaning produce continuous energy changes.
Energy is changed only by discrete amounts aka quantized and line spectrum is quantized and not continuous
What happens when an electron is at it’s highest energy level
Atom is ionized
What is ionization energy
Energy needed to remove an electron from each atom in a mole of gaseous atoms
Why do lines with higher energies converge
Energy levels in the atoms are closer at higher energy
What foes quantum theory suggest
Electrons/particled having wave properties
What was wrong with Bohrs model
It applied well to hydrogen. Not other complex atoms. It assumes electrons trajectory can be precisely described. An electrons position cannot known by means of radiation as this will give it a kick and disturb the motion and send hurtling off in a random direction
What’s heiseinbergs uncertainty principle
We cannot know the position of an electron at a given moment of time
We can only predict where it’s likely to be ie spread in an electron cloud
What is an atomic orbital
Volume if space around nucleus in which there is maximum probability of finding a specified electron