Chapter 5.2 and 5.3 Flashcards
Matter
Anything that occupies space and has masss
Nucleus
Contains protons and neutrons
Protons
Positively charged particles
Neutrons
Have no charge
Electrons
Negatively charged particles which surrounds the nucleus of an atom.
Atoms with the same number of _____ are all the same type of chemical ____.
Protons, element.
An element may have many _____: atoms with the same number of protons but different numbers of ____.
Isotopes, neutrons.
Molecules
Groups of atoms bound together by shared electrons.
Bohr Model
Proposed by Niels Bohr. An incomplete model with likens the atom to that of the solar system with the nucleus at the center and electrons orbiting around the nucleus.
What is incomplete about the Bohr Model?
Electrons are smeared around the nucleus in a quantum mechanical clouds of probability. It is impossible to simultaneously pin down their exact location and velocity.
What is a good analogy for atomic energy levels
A book case. Atoms can take different energy levels, but cannot take levels in between. The states in other words are discrete.
Ground State
The lowest possible energy state for a system. E1 The electron has minimal energy Will remain at the lowest energy state unless it gets energy from outside.
Excited States
Energy levels above the ground state.
Decay
When an electron goes from a higher energy state to a lower energy state. Usually by emitting a photon.
Emission
Where a photon is released when an electron decays from a higher energy state to a lower energy state.
How is color related to energy states.
Atoms can only emit light at certain wavelengths due to electrons decaying form one energy state to another.
Emission Line
The line(s) of emitted light from atoms corresponding to the light created when light is emitted.
Continuous spectrum
White light spreads out to rainbows of colors when passing through a prism.
Absorption.
The process by which atoms capture the energy of passing photons.
Absorption Line
The dark line seen in spectrum caused by atoms absorbing certain wavelengths of light.
Why may you observe an emission line and an absorption line for the same gas when looking at it in different directions?
Light can be absorbed and readmitted by atoms, but the direct changes as a result. So you may see an absorption line when viewing from one angle but a emission line when looking at the same gas from another angle.
How are emission lines and absorption lines useful to scientists.
Allows us to understand the composition of distant objects. Because all hydrogen atoms have the same energy states available to them and thus have the same emission and absorption lines. Can also measure the abundance of elements based on the strength of the lines. Can also determine the temperature, density, and pressure of the material .
Solar Abundance
The relative abundance of materials in the sun which is used as a standard reference for other objects.
T/F When an atom decays can be predicted by scientists.
False, scientists can estimate the average time for an atom to decay but the decay happens at a random moment and cannot be predicted with absolute certainty. .
Doppler Effect
The change in wavelength of sound or light as a result of the relative motion of the source towards or away form the observer.
Rest Wavelength
The wavelength of light that is seen coming form an object at rest with respect to the observer.
Doppler Shift
The amount by which the Doppler effect shifts the wavelength of light.
Radial Velocity
The component of velocity directed towards or away form the observer. + further away - closer.
Blueshift
The Doppler shift towards shorter blue wavelengths of light from an approaching object.
Redshift
The Doppler shift towards longer wavelengths of light from an approaching object.
Reflected Light
Occurs when Light reflects off a surface of an object.
Scattered Light
Occurs when light encounters tiny particles and is redirected.
Refracted Light
Occurs when light flows through a different medium and is bent. Rainbows and prisms.
