Unit 3 Test Flashcards
quantum mechanical model
A model that explains the behavior of absolutely small particles such as electrons and photons and explains the strange behavior of electrons
electromagnetic radiation
A form of energy embodied in oscillating electric and magnetic fields aka light
amplitude
The vertical height of a crest (or depth of a trough) of a wave; a measure of wave intensity and determines light’s brightness, the higher it is the brighter the color gets
wavelength (λ)
the distance between adjacent crests (or any two analogous points) and is measured in units such as meters, micrometers, or nanometers, determines the color
frequency (ν)
For waves, the number of cycles (or complete wavelengths) that pass through a stationary point in one second, directly proportional to the speed at which the wave is traveling. Units include cycles per second (cycle/s) and Hertz (Hz)
formula for frequency?
v=c/λ, c=speed of light, λ = wavelength
electromagnetic spectrum
The range of the wavelengths of all possible electromagnetic radiation
gamma (γ) ray
The form of electromagnetic radiation with the shortest wavelength and highest energy. produced by the sun, other stars, and certain unstable atomic nuclei on Earth. (10^-11 meters & 10-1044 J)
X-ray
Electromagnetic radiation with wavelengths slightly longer than those of gamma rays; used to image bones and internal organs ( 1 x 10^-11 - 1 x 10^-8 m & 2 x 10^-17 - 2 x 10^-14 J)
ultraviolet (UV) radiation
Electromagnetic radiation with slightly smaller wavelengths than visible light aka as the component of sunlight that produces a sunburn or suntan (1 x 10^-8m & 5 x 10^-19 - 2 x 10^-17J)
visible light
those frequencies of electromagnetic radiation that can be detected by the human eye (4-7 x 10 -6 m & 10-19 J)
infrared (IR) radiation
Electromagnetic radiation emitted from warm objects, with wavelengths slightly larger than those of visible light ( 10^-5 m 2 x 10^-22 - 3 x 10^-19J)
microwaves
Electromagnetic radiation with wavelengths slightly longer than those of infrared radiation; used for radar and in microwave ovens (10^-1m)
radio waves
The form of electromagnetic radiation with the longest wavelengths and smallest energy; used to transmit the signals responsible for AM and FM radio, cellular telephone, television, and other forms of communication (10^3 m)
What is the electromagnetic spectrum from the lowest to the highest energy?
radio, microwave, infrared, visible, ultraviolet, x-ray, gamma
interference
The superposition of two or more waves overlapping in space, resulting in either an increase in amplitude or a decrease in amplitude
constructive interference
The interaction of waves from two sources that align with overlapping crests, resulting in a wave of greater amplitude
destructive interference
The interaction of waves from two sources that are aligned so that the crest of one overlaps the trough of the other, resulting in cancellation.
diffraction
The phenomena by which a wave emerging from an aperture spreads out to form a new wave front
what’s the equation for energy?
E = hv or E=hc/(λ)
h, called Planck’s constant
v, frequency
c, speed of light
λ, wavelength
photoelectric effect
The observation that many metals emit electrons when light falls upon them
order the visible color spectrum from lowest wavelength to highest
Violet - shortest wavelength, around 380-450 nanometers with highest frequency. …
Indigo - 420 - 440 nm.
Blue - 450 - 495 nm.
Green - 495 - 570 nm.
Yellow - 570 - 590 nm.
Orange - 590 - 620 nm.
Red - longest wavelength, at around 620 - 750 nanometers with lowest frequency.
order the visible color spectrum from lowest frequency to highest
Red: 400–480 THz
Orange: 480–510 THz
Yellow: 510–530 THz
Green: 530–600 THz
Blue: 600–670 THz
Indigo: 670–700 THz
Violet: 700–750 THz
order the visible color spectrum from lowest energy to highest
red (limit) 1.77
red 1.91
orange 2.06
yellow 2.14
green 2.25
cyan 2.48
blue 2.75
violet (limit) 3.10
emission spectrum
The range of wavelengths emitted by a particular element; used to identify the element; a series of discrete lines, each corresponding to a specific wavelength (and therefore energy) of light emitted by an atom or molecule
Bohr Model
a model of the atom where the electron travels around the nucleus in circular orbit. This model’s orbits exist only at specific, fixed distances from the nucleus, and the energy of each orbit is also fixed, or quantized also known as stationary states and suggested that, although they obey the laws of classical mechanics, they also possess “a peculiar, mechanically unexplainable, stability.”
Photons
particles of light that carry energy
Ground State
the lowest energy state of an atom, where the electrons are in their lowest possible energy levels
Excited State
A higher energy state of an atom, where one or more electrons have absorbed energy and moved to a higher energy level
How do atoms emit light?
Atoms emit light when electrons transition from higher energy levels to lower energy levels, releasing energy in the form of photons
Absorption
An electron absorbs a photon and moves to a higher energy level
Excitation
The electron is in an excited state
Emission
The electron returns to a lower energy level, emitting a photon in the process
de Broglie
a fundamental concept in quantum mechanics, which proposes that all matter exhibits wave-like behavior
de Broglie wavelength (λ)
λ = h/p or λ=h/mv
λ is the wavelength,
h is Planck’s constant (6.626×10^−34)
p is the momentum of the particle
m is mass (kg)
v is velocity (m/s)
Heisenberg’s Uncertainty Principle
a concept that states that there is fundamental limit to the precision to the certain pairs of physical properties of a particle. The more precisely one property is measured, the less precisely the other can be controlled, determined or known. For example, the more accurately the position of a particle is measured, the less accurately its momentum can be known.
orbital
A probability distribution map, based on the quantum-mechanical model of the atom, used to describe the likely position of an electron in an atom; also, an allowed energy state for an electron.
Schrödinger equation
an equation that describes how the quantum state of a physical system changes with time. It is essential for understanding the behavior of particles at the atomic and subatomic levels. There are two main forms of the Schrödinger equation: the time-dependent and the time-independent equations.
quantum number
One of four interrelated numbers that determine the shape and energy of orbitals, as specified by a solution of the Schrödinger equation
What does n represent?
Principal Quantum Number (n): Indicates the main energy level or shell. Can take positive integer values (n=1,2,3,…).
Higher n values correspond to orbitals that are farther from the nucleus and have higher energy.
What does l represent?
Angular Momentum Quantum Number (l): Defines the shape of the orbital. Can take integer values from 0 to n−1.
Each value of l corresponds to a different type of orbital: l=0 (s orbital), l=1 (p orbital), l=2 (d orbital), l=3 (f orbital), and so on.
What does ml represent?
Magnetic Quantum Number (m): Describes the orientation of the orbital in space. Can take integer values from −l to +l, including zero.
What does ms represent?
Spin Quantum Number (ms): Describes the spin of the electron within the orbital in space, can take the values of + or - 1/2
What are the different types of orbitals?
s, p, d, f
what the s orbital?
l = 0, spherical shape, only one orientation (ml=0)
what is the p orbital?
l = 1; dumbbell shape, three orientations (ml = -1,0 +1)
what is the d orbital?
l = 2, more complex shapes, often described as cloverleaf or double dumbbell, five orientations (ml = -2, -1, 0, +1, +2)
what is the f orbital?
l = 3, even more complex shapes, seven orientations (ml = -3,-2,-1,0,+1,+2,+3)
What’s the wavelength of a hydrogen transitioning from n=5 to n=2 and its color?
434 nm and purple
What’s the wavelength of a hydrogen transitioning from n=4 to n=2 and its color?
486 nm and green
What’s the wavelength of a hydrogen transitioning from n=3 to n=2 and its color?
656 nm and red
principal level (shell)
The group of orbitals with the same value of n
sublevel (subshell)
Those orbitals in the same principal level with the same value of n and l
the number of sublevels in any level is equal to
n, the principal quantum number
the number of orbitals in any sublevel is equal to
2l+1
the number of orbitals in a level is equal to
n^2
the number of electrons
2n^2
how to find the change in energy that occurs in a hydrogen atom when an electron changes energy levels?
change in E = E final - Einitial
how do i find the wavelength when an electron is transitioning between two energy levels?
wavelength = hc/E
aufbau principle
The principle that indicates the pattern of orbital filling in an atom