Electronic Structure Of Atoms Flashcards
What is an energy level?
It’s a region of definite energy within an atom that electrons occupy
What elements have the same number of electrons in the outer most energy level
Are in the same group
How do elements emit light and give an example
When the atoms of the elements are supplied with energy under certain
conditions
Energy can be supplied by a flame
What flame colour does barium have?
Yellow-green
What flame colour does copper have?
Blue-green
What flame colour does lithium have?
Deep red
What flame colour does potassium have?
Lilac
What flame colour does sodium have?
Yellow
What flame colour does strontium have?
Red
Flame test
- crush salt to be tested with mortar and pestle
- dip soaked splint in salt and put splint in flame
- note colour
- repeat with other salts and note colour
Give example of flame tests in everyday life
Firework displays - strontium and barium
What is the discharge tube used for?
If an element is easily vaporised, it emits light of a characteristic colour when placed in discharge tube at low pressure and high voltage
What is a spectroscope?
It analyses light emitted by elements
What can flame tests be used for
To distinguish between different metals in their compounds
What is white light?
Mixture of visible light of all wavelengths
What occurs in a spectroscope when analysing white light?
The light waves are bent to different extents forming a continuous brand of colours or continuous spectrum [red to violet]
What is viewed when light emitted from a discharge tube containing hydrogen is analysed using a spectroscope?
A series of coloured lines of definite wavelength against a dark background is observed = line spectrum
How could you differ different elements?
By their emission spectrum. The emission spectrum of an element is characteristic of that element and is different from that of any other element
Why are certain colours not seen in the hydrogen/line spectrum?
Certain colours not able to be absorbed
What kind of light do elements emit?
Visible light and light in the ultraviolet and infrared regions
What does the hydrogen spectrum include?
Series of lines in both the visible and ultraviolet regions
What contains all the lines in the visible region of the hydrogen spectrum?
The Balmer series
What contains the lines in the ultraviolet region of the hydrogen spectrum?
Lyman series
What contains the lines in the infrared region of the hydrogen spectrum?
Paschen series
What does each element have?
A characteristic emission spectra and an absorption spectra
What is the absorption spectrum?
It’s the spectrum that is observe after the white light has been passed through an element
What does an absorption spectrum consist of?
A series of dark lines against a coloured background. The dark lines are at exactly the same wavelengths as the coloured lines in the emission spectrum of that element.
How can you measure the amount of an element in a sample
From the amount of light absorbed - atomic absorption spectrometer