Atomic Structure Flashcards
In the nucleus, there is…
Neutrons and protons
Most of the mass in the atom is because?
Nucleus (protons and neutrons)
How do electrons move?
In orbitals
The orbitals in an atom take up?
Most of the volume
The diameter of the nucleus is what compared to the rest of the atom?
Very small
What is the relative mass and charge of protons?
1 and +1
What is the relative mass and relative charge of a neutron?
1 and 0
What is the relative mass and charge of an electron?
1/2000 and -1
What does the mass number tell you?
Total number of neutrons and protons
What does the atomic number tell you?
The number of protons
For neutrally charged atoms, what can we say about the number of protons and neutrons?
They are equal
If they atom is charged, what can we say about the number of protons and electrons?
They are unequal
In a positively charged ion, there are
More protons than electrons
In a negatively charged ions, there are
More electrons than protons
Define isotope
Atoms with the same number of protons and electrons but different number of neutrons
Do isotopes have the same chemical properties? Why?
Yes
The same number and arrangement of electrons i.e the same electron configuration
Do isotopes have the same physical properties? Why?
No, but only slightly
Depends on mass of an atom
Examples of how physical properties of an isotopes differ
Different densities, rates of diffusion
What was Dalton’s model of an atom like?
Solid spheres
Different spheres make up the different elements
What was Thompson’s model of the atom like?
Came up with the ‘plum pudding’ model
Discovered electrons
Electrons were surrounded by positively charged ‘pudding’
What was Rutherford’s model of an atom like?
Tiny positively charged nucleus surrounded by a ‘cloud’ of negative electrons. Most of the atom was empty space
How did Rutherford prove that Thompson’s plum pudding model was wrong?
Through the gold foil experiment
If Thompson’s model was right, what would the experiment shown? Explain why
That all of the alpha particles would be deflected
The positive alpha particle would be repelled by the positive atom
What actually happened during the gold foil experiment?
Most of the particles went straight through the foil with only a small number being deflected backwards
What was Rutherford’s model called?
Nuclear model of the atom
What was wrong with Rutherford’s model?
The cloud of electrons would collapse into the nucleus, causing the atom to dissipate
What did Bohr propose in his model?
That electrons are split into orbitals of fixed energy.
What happens when an electron moves across a shell?
Electromagnetic radiation is absorbed or emitted
When an electron is moving to a shell closer to the nucleus, then…
Electromagnetic radiation is emitted
When an electron is moving to a shell that is further away from the nucleus, then…
Electromagnetic radiation is absorbed
Atoms are made up of?
Protons, neutrons and electrons
How do you work out whether electromagnetic radiation is emitted or absorbed during the movement of electrons?
The arrows go in opposite directions
Why is Bohr’s original model wrong?
Not all electrons in a shell have the same energy level
How has Bohr’s model been refined?
Now includes subshells.
Despite Bohr’s model not being completely correct, why is it still used?
Simple and explains many experimental observations
Define relative atomic mass
The average mass of an atom of an element, taking in consideration abundance and isotopes, in comparison 1/12th of a carbon-12 atom
Define relative isotopic mass
The mass of an atom of an isotope of an element compared with 1/12th of a carbon-12 atom
Define relative molecular mass
The average mass of a molecule, taking into consideration abundance and isotopes, compared with 1/12th of a carbon-12 atom
Explain the first step of electrospray ionisation
The sample is dissolved in a polar solvent and pushed through a capillary needle at high pressure. A high voltage is applied to it, causing the particles to lose an electron. The ionised particles are separated from the solvent, leaving a gas of positive ions
Explain the second step of time of flight
All the ions are accelerated by an electromagnetic field, giving each ion the same kinetic energy as the rest. This means that ions with a smaller mass/charge ratio are more accelerated as they are lighter
What happens during the third stage of time of flight?
The ions leave the electromagnetic field at a constant speed and a constant kinetic energy and therefore continue through the drift region in the same state
What happens in the forth region?
Ions with lower mass/charge will reach the detector first. The detector records the current created when the ion hits it and the amount of time the ion takes to travel through the spectrum, which is then used to create a mass spectrum
Why must the time of flight have a vacuum?
So that the gas sample particles do not collide with other particles and distort the results
What is the difference in time of flight method using electro bombardment?
They use an electro gun to remove an electron of the atom
How is a current created in time of flight?
The electron is given back to the ion
What are the two problems with electro bombardment?
Fragmentation
The removal of more than one electron
What is electro spray used to analyse?
Large bio molecules
Polar organic molecules
What polar solvents are used in electro spray?
Water, methanol, or both
What is the current used in electro spray?
4000 volts
What is the fancy word for ionised spray?
Nebulise
How is the solvent evaporated?
Through the high voltage
What is the fancy word for solvent evaporation?
Desolvation
Why is the sample dissolved in a polar substance?
Provides the H+ ion
Each shell is given what help use identify it?
Principal quantum number
As the shell furthers from the nucleus, the principal quantum number _________ and the energy __________?
Increases and increases
Each individual shell is divided into?
Subshells
What are the types of subshells?
S, P, D, F
How many orbitals does the S subshell have? And how many electrons can it hold?
1 and 2
How many orbitals in the p subshell? And how many electrons can it hold?
3 and 6
How many orbitals are there is the p subshell? And how many electrons can it hold
5 and 10
How many orbitals are there in the f subshell? And how many electrons can it hold?
7 and 14
How many electrons can each individual orbital hold?
2
How do we write short hand electron configuration?
The last noble gas in square brackets and additional subshells listed after
What are the two elements that do not form normal electron configuration? Why?
Chromium and copper
They donate one of their 4s electrons to the 3D orbital, because it is more stable with a full or half-full 3D orbital
When transition metals become an ion they…
Lose their electron from the 4s orbital before their 3D orbital
The S block elements lose their outer electrons
to form positive ions with an inert gas configuration
Those in the p block gain electrons
To form negative ions with inert gas configuration
Those in group 0 have…
A full outer shell so they are inert
What are the three ways electron configuration can be shown
Subshell notation
Arrows in boxes
Energy level diagram
What are the three rules to working out electron configuration
Electrons fill up the lowest energy subshell first
Electrons fill orbitals in a sub-shell singly before they start sharing
For ions, add or remove the electrons from the highest occupying sub-shell
