C1: Atomic Structure Flashcards
Describe an Atom and how we draw them
Particles found in the nucleus are called nucleons. Protons and neutrons are found in the nucleus.
The nucleus and the electrons are very small compared to the overall size of the atom, which is mostly empty space. The diameter of a nucleus< 1/20000 of an atom.
Electrons have certain energies so we draw 2d dot cross diagrams, but remember atoms are 3d and not flat
How are ions formed?
Ions are formed by (neutral) atoms gaining or losing electrons to form anions or cations
what is meant by the terms ‘atomic (proton) number’ and ‘mass number’
Atomic number is the number of protons or the number of electrons. Atomic mass is the number of protons + the number of neutrons.
Why do the number of protons not change during a chemical reaction?
Chemical reactions involve the losing/gaining or sharing of electrons. Reactions do not involve the nucleus and so the number of protons in an atom does not change during a chemical reaction.
How many electrons can the 1st, 2nd, 3rd shell hold?
2,8,8
what are isotopes?
atoms of the same element with the same atomic/proton number, but with a different number of neutrons.
How do you analyse and interpret data from mass spectrometry to calculate relative atomic mass from relative abundance of isotopes?
the x axis should have the masses. the peaks should show the relative abundance. take the abundance and masses and find the Ar for the element
Describe mass spectra of boron
There are two peaks in the above mass spectrum of boron, so there are two isotopes of boron with m/z values of 10 and 11. The mass numbers of the two isotopes are 10 and 11.
The ratio of the peaks for m/z 10:11 is 1:4, so there are four times as many atoms of boron with a mass of 11 as there are with a mass of 10.
In this sample of boron, 80% of the atoms are boron-11 (115
B) and 20% are boron-10 (105
B).
