Topic 2: Atomic Structure Flashcards
What are the sub-atomic particles in an atom?
protons, neutrons and electrons
Where are protons and neutrons located?
In the nucleus
Where are electrons located?
In energy levels within the atom
What is the atomic number?
The number of protons in an atom; the number that gives an atom its identity
How do you find the mass number?
Add protons and neutrons
How do you find the number of neutrons?
Mass number minus protons
Why is the number of protons and electrons the same?
Because atoms are always neutral
What happens in ions?
The number of protons and neutrons remains the same, but the number of electrons changes
What are isotopes defined as?
Atoms of the same element that have the same number of protons, but a different number of neutrons
What is Relative Atomic Mass (RAM) (Ar) defined as?
The average of the masses of the isotopes in a naturally occurring sample of the element, relative to the mass of 1/12 of an atom of C12.
What is a mass spectrometer?
A device used to find the relative mass of elements, isotopes and compounds
How does a mass spectrometer work?
It separates positive ions according to mass/charge ratio. The ions with the lower m/z ratio are deflected more than those with a higher
What does a mass spectrum tell us?
On the X-axis, it shows the mass/charge ratio of different isotopes in an element. On the Y-axis, it shows isotopic abundances
How do you find the RAM of an element from the abundance of its isotopes and their mass/charge ratios?
mass/charge ratio x percent abundance over percent abundance added together
What does the Bohr theory claim?
Each energy level of an atom can hold a certain number of electrons. The main energy level (principal quantum number) is n. The maximum number of electrons in each shell = 2n^2
What are the general rules of the Bohr theory?
- energy levels are filled lowest to highest
- first two levels must be filled before next level
- third is “pseudo filled” at 8, then fourth can be filled
- this works for elements up to 20
What is the electromagnetic spectrum?
The range of wavelengths of electromagnetic radiation
What is the electromagnetic spectrum?
Radio, Microwaves, Infrared, Visible, Ultraviolet, X-Ray, Gamma
Raging Martians Invaded Venus Using X-Ray Guns
Radio, Microwaves, Infrared, Visible, Ultraviolet, X-Ray, Gamma
Which end of the spectrum has lowest energy, longest wavelength?
Radio
Which end of the spectrum has highest energy, shortest wavelength?
Gamma
What is the continuous spectrum?
Shows all wavelengths of VISIBLE LIGHT (ROYGBIV). Energy increases towards violet, wavelength increases towards red
How are line spectra produced?
Electrons transition between energy levels by absorbing or emitting energy.
Electrons absorb energy when transitioning to higher levels.
They emit energy when transitioning to lower levels
How is the absorption line spectrum produced?
When an electron absorbs energy and transitions to higher-level from n=2 level
