The atom and redox Flashcards
Where’s a proton found, what’s it’s mass, and what’s it’s charge?
Found in nucleus, has a mass of 1, and charge of plus 1
Where’s an electron found, what’s it’s mass, and what’s it’s charge?
Found orbiting around the nucleus, Has a mass of 1/2000, and has a charge of -1
Where’s a neutron found, what’s it’s mass, and what’s it’s charge?
Found in nucleus, has a mass of 1, has no charge
What’s the atomic number of an element?
The number of protons in the nucleus of the atom of an element
How are ions different from normal atoms?
Normal atoms have the same amount of protons and electrons, ions have different amounts
How to find the charge of an atom?
Number of protons subtract the amount of electrons
What’s an isotope?
An atom of the same element, with different amounts of neutrons, and therefore different masses
What’s the mass number of an element?
Protons plus neutrons
Where is most of the mass concentrated in an atom?
In the nucleus
Explain what is meant by the idea of relative mass, and why do we use it?
It’s comparing the mass to other atoms, we use it because atoms have such small masses
What has been chosen as the international relative mass standard? Why?
Carbon 12 isotope, because it can easily be obtained in an isotopic pure state, and it’s unreactive
What is relative isotopic mass?
The mass of an atom of an isotope, compared with 1/12 of the mass of an atom of carbon 12
Formula for finding the mass of an isotope?
(Relative abundance 1 x mass 1) + (relative abundance 2x mass 2) divided by total relative abundance
What is relative atomic mass?
The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon 12
How can you find the percentage abundance experimentally?
With a mass spectrometer
Brief outline how the mass spectrometer works?
Atoms can be deflected by a magnetic field provided they are first turned into a cation. The deflected ions are detected and displayed on a mass spectrum as a mass over charge ratio on x axis (this means if the charge is just +1, it’s basically just the mass), and relative abundance on y axis
How do you know how many isotopes there are from a mass spectrum?
It’s the amount of lines
How to calculate the relative abundance of each isotope from a mass spectrum?
Add up all the lines (their abundances), and divide the isotope you want by that value, then multiply by 100 to find %
What is relative molecular mass?
The weighted mean mass of a molecule compared to 1/12th of the mass of an atom of carbon 12
What is relative formula mass?
The weighted mean mass of a formula unit, compared to 1/12th of the mass of an atom of carbon 12
What’s the definition of the first ionisation energy?
Energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of +1 ions
Show the first ionisation energy of potassium?
K(g) = K+(g) + e-
What are the 3 factors that determine the amount of energy which is required to remove an outer electron?
Distance of the electron from the nucleus
The charge on the nucleus
The number of electrons in inner shells
What does shielding mean?
When inner electrons reduce the force of the attraction from the nucleus to the outer electron(s)
Write the second ionisation energy of potassium?
K+(g) = K2+(g) + e-
Why is the second ionisation energy always higher than the first?
Because now you are removing an electron from a species with a positive charge, so all the electrons have been drawn nearer to the nucleus
Why is the third ionisation of magnesium far higher than the second?
Because after the first 2 electrons you are now taking from the inner shell, which has far less electron shielding so it experiences a far higher attraction to the nucleus
What can successive ionisation energies show you about an atom?
It’s electronic structure
In a simulated photoelectron spectrum, what does the position of the peak on the x axis determine?
The amount of energy required to remove an electron from a particular energy level
