10 Chem Chapter 4 Electron Configuration

Electron Configuration Waves: -

Light travels in waves , it is a form of electromagnetic radiation

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All waves can be described in terms of four characteristic – amplitude, wavelength, frequency, and speed.

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Amplitude is the height of a wave

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Wavelength is the distance between the crests of each wave

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Frequency of a wave tells how fast the wave goes up and down (narrow or wide)

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Relationship between wavelength and frequency is Wavelength = speed of light/frequency

Visible Spectrum Quantum Theory Planck proposed that there is a fundamental restriction on the amounts of energy that an object emits or absorbs, and he called each of these pieces of energy a quantum. -

Quantum means fixed amount

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The modern idea of the quantization of energy is that an object an absorb or emit any amount of energy so that the energy it can possess forms a continuum of values.

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Planck’s theory relates the amount of energy to frequency: E = hv

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The “h” in the equation is Planck’s constant

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Planck’s theory proposes : all energies absorbed or emitted by atoms are quantized, which means their quantities are restricted.

Photoelectric Effect -

The Photoelectric Effect proposes that tiny particles of light called quota photons carry an amount of energy that is given by Planck’s equation , E = hv

Dual Nature of Radiant Energy -

The Dual Nature of Radiant Energy is the idea that light consists of tiny particles , or photons

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It also says that light possesses properties of both particles and waves

Line Spectra -

A spectrum that contains only certain colors, or wavelengths, is called a line spectrum

Bohr Model of the Hydrogen Atom -

Shows the different levels of energy in an atom

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Electrons have ground states of 1 and exited states of numbers higher than 4

Matter Waves -

Matter Waves are the wavelike behavior or particles

Heisenberg’s Uncertainty Principle -

The Uncertainty Principle states that the position and momentum of a moving object cannot simultaneously be measured and known exactly

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Measurements can change depending on what you are trying to measure

Probability and Orbitals -

Electron Density refers to the density of an electron cloud

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Orbitals are the probability of finding electrons in certain regions of an atom

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An Atomic Orbital is a region around the nucleus where an electron with a given energy Is likely to be found

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Different orbitals such as s, p, d, and f have different shapes: S orbitals are spherical in shape P orbitals are dumbbell shaped D and F shapes are much more complex

Orbitals and Energy -

Principal energy levels with the quantum number n contain electron with energies of 1 to 2 to 3

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Each principal energy level can also be divided into sub levels

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For instance, there is 1 sub level when n = 1 , 2 sublevels when n = 2, etc.

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Each sublevel has its own orbitals, like how the 1s sublevel has an orbital of 1s

Electron Spin -

Electrons can spin on their own axis clockwise or counterclockwise

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The spinning creates a magnetic field, creating north and south poles

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If both electrons have parallel spins they will create a magnetic effect

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But if electrons have opposite spins, the magnetic field will cancel each other out

Maximum Electrons in Sublevels

sublev el s p d f

numer of orbitals 1 3 5 7

max # of electr ons 2 6 10 14

Electron Configuration -

Electron Configuration is the distribution of electrons among the orbitals of an atom

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Electron configurations are determined by distributing the atom’s electrons among levels, sublevels, and orbitals based on a set of stated principals

Determining Electron Configuration -

The Aufbau Principle: Electrons are added one at a time to lowest energy orbitals available until all the electrons in the atom have been accounted for

Exceptions to the Aufbau Principle: Chromium, Copper, exceptions are due to subtle electron- electron interactions in orbitals with similar energies -

The Pauli Exclusion Principle: An orbital can hold a maximum of 2 electrons. An orbital with one electron is said to be unpaired

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Hunds’ Rule: Electrons occupy equal – energy orbitals so that a maximum number of unpaired electrons results.

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Orbital Diagram: represent the number of electron in each orbital with boxes and arrows to show the magnetic properties of each electron