Atomic Structure Flashcards
What is the symbol proton number?
Z
What is the symbol for the atomic mass?
A
What did J.J Thomson think an atom was?
He discovered that atoms were divisible and that electrons (which were smaller and lighter) were imbedded inside a positively charged sphere (plum pudding model)
What did Ernest Rutherford discover?
He fired alpha partials at a thin film of gold and instead of bouncing off, most particals passed through. This lead to the idea that an atom was mostly empty space with a positive nucleus and orbiting electrons
What must electrons do when moving between orbits?
They must emit or absorb electromagnetic radiation of a particular frequency
What is the atomic mass?
1/12 of the mass of a single carbon-12 atom
What is the mass and charge of a proton?
Mass = 1.0073amu
Charge = +1
What is the mass and charge of a neutron?
Mass = 1.0087amu
Charge = no charge
What is the mass and charge of an electron?
Mass = 0.00055amu
Charge = -1
What does the nucleus contain and what is its charge?
Protons and neutrons
Positive charge
What are electron shells split into?
Sub-shells which have slightly different energies
What do sub-shells split into?
Orbitals
What is the mass number of an atom?
Protons + Neutrons
What are positive ions called?
Cations
What are positive ions?
Atoms which have lost an electron
What are cations attracted to?
The cathode and anything negativity charged
What are negative ions called?
Anions
What are negative ions?
Atoms which have gained electrons
How do you calculate the charge of an ion?
Charge = number of protons - number of electrons
What will the overall charge of any chemical substance and why?
0 because cations will always be accompanied by anions in solid or in solution
What is the theory of electroneutrality?
That cations will always be accompanied by anions
What are isotopes?
Atoms of the same element that have the same number of protons but a different number of neutrons
What effects do isotopes have on the elements chemistry?
Since neutrons have no electric charge and chemistry is largely about electrostatic interactions, the change in mass rarely effects it’s chemistry
What are the steps in mass spectrometry ?
- Ionisation
- Acceleration
- Deflection
- Detection
What happens in stage 1 of mass spectrometry?
The sample is vaporised and then passes into an ionising chamber where they are hit with a beam of electrons to form positively charged ions
What happens in stage 2 of mass spectrometry?
An positive electric field is applied to the chamber and the ions repel them and shoot towards 3 negatively charged slits
What happens in stage 3 of mass spectrometry?
What happens in stage 4 of mass spectrometry?
What can happen during the ionisation stage of mass spectrometry when using electron impact?
The sample could fragment
What is the equation for kinetic energy?
Kinetic energy = 1/2 x mass x velocity2
What is the time of flight calculation?
Time = distance / (square root (2 x kinetic energy) / mass)
What type of ion travels faster in mass spectrometry?
The lighter ions
What charge does the detection plate have in mass spectrometry?
Negative charge
How do you calculate the relative atomic mass ?
( isotope abundance x mass isotope mass number ) + ( isotope abundance x mass isotope mass number )
How many electrons can orbitals contain?
They can hold a maximum of 2 electrons
What do physical properties of N element depend on?
The mass of the atom
What do chemical properties of an element depend on?
The number and arrangement of electrons
