1.5 & 1.6: Electronic Configuration Of Atom Flashcards
(58 cards)
What are the 2 important concepts of the Quantum Theory?
- Electrons can be described as waves by the Schrondinger equation
- Uncertainty principle
What is the Schrondiger equation?
An equation that describes an electron’s properties in terms of quantum numbers
What is the uncertainty principle?
The idea that both the exact location and velocity of a subatomic particle can never be known at the same time
What are the 3 observations that quantum theory shows and classical mechanisms can’t?
- Spectra of light emitted by atoms
- Stability of atoms
- Wave-particle duality
What does measuring the energy of a photon allow us to determine?
The energy difference between levels - this indicates energy levels are not equally spaced
What is ionisation energy?
The measure of the amount of energy needed to remove electrons from atoms/ions
Define ‘First Ionisation Energy’
The amount of energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous positive ions
What gives us evidence for the arrangement of electrons within an atom?
Patterns in ionisation energies
What is electron affinity?
The amount of energy needed to add electrons to atoms/ions
Define ‘First Electron Affinity’
The amount of energy required to add one mole of electrons to one mole of gaseous atoms to form one mole of gaseous negatively charged ions
Why are first electron affinities always negative?
Energy is released on addition of the electron
What shows the stability of a negative ion?
Electron affinity - the more negative = more stable ion formed
What is the trend in Atomic size:
1. Down a group
2. Across a period
Atomic size increases down a group
Atomic size decreases across a period
What is the trend in first ionisation energy:
1. Down a group
2. Across a period
First ionisation energy decreases down a group
First ionisation energy increases across a period
What is the trend in Atomic size:
1.
What is the trend in Atomic size:
1.
What is the trend in First electron affinity:
1. Down a group
2. Across a period
First electron affinity becomes less negative down a group - less stable ion
First electron affinity becomes more negative across a period - more stable ion
What is an orbital?
A region in space where there is a given (usually 95%) probability of finding a particular electron
Cannot specify the exact position of an electron in an atom
What are quantum numbers?
The various energy levels available within an atom in which electrons can reside
What 3 things do quantum numbers show?
- The position of an electron in an atom
- The direction of spin of the electron
- The energy and angular momentum of an electron
What are the 4 quantum numbers required to specify the character of an atom?
- Principle Quantum Numbers (n)
- Azimuthal or subsidiary Quantum Numbers (l)
- Magnetic Quantum Numbers (m)
- Spin Quantum Numbers (s)
What do principle energy levels/ shells correspond to?
The Principle Quantum Number (n)
What are Principle Quantum Numbers traditionally referred to?
Letters K, L, M …..
Where the K shell n =1
L shell n =2 etc
What happens to energy levels in complex atoms when n increases?
They get closer
