Chapter 7: Atomic Structure and Periodicity Flashcards
What is electromagnetic radiation
One of the means by which energy travels
through space
fill in the blanks
Electromagnetic Radiation exhibits ________________ behavior, and travels at ________________________ in a vacuum
Exhibits wavelike behavior and travels at the speed of light in a vacuum
What is a wavelengh (λ)
Distance between two
consecutive peaks or troughs in a wave
What is frequency (v)
Number of waves (cycles) per
second that pass a given point in space
What is the unit for the speed of light (c)
2.9979 × 10^8 m/s
What is the realtionship between wavelength and frequency
an inverse relationship
Short-wavelength radiation has a _____________
frequency when compared to long-wavelength radiation
higher
What did Max Planck say
Postulated that energy can be gained or lost only in whole number multiples of h ν
Formula for representing change in energy
ΔE = nhv
n - Integer
h - Planck’s constant
ν - Frequency of electromagnetic radiation absorbed oremitted
What was the conclusion from Planck’s Postulate
Energy is quantized and can occur in discrete units of hν
Formula to calculate quantum energy
ΔE = hv
What did Albery Einstein propose
Proposed that electromagnetic radiation is a stream of particles called photons
What is the photoelectric effect
Phenomenon in which electrons are emitted from the surface of a metal when light strikes it
Regarding the photoelectric effect:
what happends when frequency of light is varied
When frequency of light is varied, no electrons are emitted by a given metal below the threshold
frequency (ν0)
Regarding the photoelectric effect:
When ν < v0:
When ν < v0 , no electrons are emitted, regardless of the intensity of the light
Regarding the photoelectric effect:
When v > v0:
- The number of electrons emitted increases with the intensity of the light
- The kinetic energy (KE) of the emitted electrons increases linearly with the frequency of the light
What is the symbol representing the minimum energy required to remove an electron
E0 = hv0
Formula by Einstein regarding energy and mass
E = mc^2
What is the dual nature of light
Electromagnetic radiation exhibits wave and particulate properties
What did Louis de Broglie claim
He postulated the wave nature of electrons and suggested that all matter has wave properties.
What is a continuous spectrum
Results when white light is passed through a prism
- Contains all the wavelengths of visible light
What is the line spectrum
The line spectrum shows only certain discrete wavelengths
What is the quantum model
The electron in a hydrogen atom moves around the nucleus in certain allowed circular orbits
- Tendency of the revolving electrons to fly off the atom can be balanced by its attraction to the positively charged nucleus
What is borh’s model
Expression for energy levels available to the electrons in the hydrogen atom
What does the negative sign imply in Bohr’s model
Negative sign implies that the energy of the electron bound to the nucleus** is lower than it would be **if the electron were at an infinite distance from the nucleus
In the Bohr model, what is the ground state
Lowest possible energy state
Is the energy of the electron in any orbit is positive or negative relative to the reference state (n = ∞)
It is negative
Formula for the calculation of change in Energy (ΔE) and Wavelength of the
Emitted Photon
Δ E = energy of final state - energy of initial state
What does it mean if in ΔE =E2-E1, ΔE has a positive value
The positive value for ΔE indicates that the system has gained energy
What happends as the electron becomes more tightly bound
As the electron becomes more tightly bound, its energy becomes more negative relative to the zero energy reference state
As the electron is brought closer to the nucleus, is energy absorbed or released from the system
it is released
How is the electron in a hydrogen atom imagined
it is imagined to be a standing wave
7.5!!!
What are quantum numbers
Series of numbers that express various properties of an orbital
- Principal quantum number (n)
- Angular momentum quantum number (l)
- Magnetic quantum number (m1)
For principal quantum numbers, what happends as the value of n increase
(3)
- The orbital becomes larger
- The electron spends more time away from the nucleus
- The energy increases since the electron is less tightly bound to the nucleus
(Energy is less negative)
What is the principal quantum number related to
Related to the size and energy of an orbital
What am I?
Has integral values (1, 2, 3, …)
Principal Quantum Number
What am I?
Has integral values from 0 to n 1 for each value of n
Angular Momentum Quantum Number
What am I?
Has integral values between 1 and -1 (includes zero)
Magnetic Quantum Number
What is the Angular Momentum Quantum Number related to
Related to the shape of atomic orbitals
For the Angular Momentum Quantum Number, what letter is each value of l assigned to?
0 = s
1 = p
2 = d
3 = f
4 = g
Each set of orbitals with a given value of l (subshell) is designated by giving the value of n and the letter for l
What is the value of the Magnetic Quantum Number related to
Value is related to the orientation of an orbital in space relative to the other orbitals in the atom
Which orbital am I?
Characterized by their spherical shape; shape becomes larger as the value of n increases
S orbitals
2 s and 3 s orbitals have areas of ———- probability separated by areas of ———- probability
2 s and 3 s orbitals have areas of high probability separated by areas of** low probability**
For s orbitals, how do you calculate the number of notes
Number of nodes is given by n-1
True or false
s orbital function is always positive in two dimensional space
False. s orbital function is always positive in three
dimensional space
Define:
nodes
Areas of zero probability in an orbital
What causes the number of notes to increase
Number of nodes increases as n increases
Where do d orbitals first appear
In level n=3
