Topic 1 Atomic Structure Flashcards
What is an atom
An atom is the smallest uncharged part of an element.
The relative mass of a proton
1
The relative mass of a neutron
1
The relative mass of an electron
1/1840 = 0.000543
What is the atomic number
The atomic number is the number of protons in an atom
What is the mass number
The total number of particles in the nucleus
(No. of protons + neutrons)
What is the no. of neutrons
Mass number - Atomic number
What are isotopes
Isotopes are the same type of atoms (same no. of protons/atomic number) but a different no. of neutrons
What is the relative atomic mass
Relative atomic mass (Ar) is the weighted mean of the atoms of a normal sample relative to 1/12 the mass of the C-12 isotope
What is the relative isotopic mass
Relative isotopic mass is the mass of an isotope of the element relative to 1/12 the mass of the C-12 isotope
What is relative molecular mass
Relative molecular mass (Mr) is the mass of a molecule relative to 1/12 the mass of the C-12 isotope
What is the relative formula mass
Relative formula mass is the sum of all the atomic masses of all the atoms in a particular formula
alternative name to hydrogen-1
protium
alternative name to hydrogen-2
deuterium
alternative name to hydrogen-3
tritium
What are the processes in a mass spectrometer
- sample is vapourised
- sample is ionised by an electron gun shooting electrons to knock off the existing electrons
- the ions are accelerated by an electric field
4.the accelerated ions pass through a magnetic field and are deflected - the ions are detected and recorded
Why must the tube in a mass spectrometer be under vacuum
so the ions won’t collide with air molecules that could affect the path the ions are taking
What m/z mean
mass/charge
What is the molecular/parent ion
the peak with the highest mass caused by the ion formed from the whole molecule
Where to find the molecular ion
the largest peak at the end of the m/z graph
Where could we use mass spectrometers in real life
-in sport to detect the use of anabolic steroids
-by pharmaceutical industries to identify synthesized compounds as possible potential drugs
Why do certain substances produce different colours when placed in flames
-the heat energy from the flame causes electrons to move to a higher energy level shell.
-the electrons drop back down again and give out energy
-this energy is given out in the form of light
-this energy drop is always same for a particular type of atom, so the flame exhibits a particular colour
Which metals atom emit coloured flames
lithium
sodium
potassium
calcium
strontium
barium
Why do some metals don’t display colours
the energy given back out is not in the visible light spectrum
what is ionisation energy
the energy required to remove an electron from an atom
Definition of first ionisation energy
the energy required to remove one electron from each atom in one mole of gaseous atoms producing one mole of gaseous ions with one positive charge
example of first ionisation
Cl (g) => Cl+ (g) + e-
What does the magnitude of the first ionisation energy tell us
the magnitude tells us about the force of attraction between the nucleus and the outer electrons
what factors influence the attraction between an electron to the nucleus depends on
-charge in the nucleus - number of protons (positive charge) in the nucleus, higher the charge, greater the attraction
-distance from the nucleus, smaller the distance, greater the attraction
-shielding from inner electrons/shells, less inner electrons/shells, greater the attraction
trends for first ionisation energies across a period
TREND 1: general increase
TREND 2: little drop from group 2 to 3
TREND 3: little drop from group 5 to 6
TREND 4: big drop from group 0 to 1/ one period to another
Reasons for TREND 1
-increase in nuclear charge
-similar shielding and distance
-attraction between outer e- and nucleus
Reasons for TREND 2
-distance and shielding increase from s to p orbital
-attraction between outer e- and nucleus decrease
-(despite higher nuclear charge)
Reasons for TREND 3
-outer electron is group 6 is sharing a p orbital
-repulsion between the electrons in the p orbital
-attraction between outer e- and nucleus decrease
Reasons for TREND 4
-large increase in distance and shielding, into a new electron shell
-attraction between outer e- and nucleus decrease
-(despite higher nuclear charge)
Which group has the highest ionisation energy
noble gases
which group has the smallest ionisation energy
group 1
what is the relative charge of a proton
1+
what is the relative charge of an electron
1-
what is the relative charge of a neutron
0
when to use RFM
could for everything
when to use RMM
non ion compounds, involving molecules,
what is a mass spectrometer used for
to determine the relative atomic and molecular mass
what does the peak on the graph for a mass spectrometer tell
number of each type of ions present, isotopes
why do peaks occur at other numbers lower, e.g. 35 and 37 for chlorine
molecules break up in the mass spectrometer
how is the RMM calculated using the graph
the mass value of the molecular/parent ion
patterns in graphs for the same compounds
molecules in the compound will always break up the same way and in the same proportion
therefore will produce the same pattern in the mass spectrograph
how to answer an ionisation energy question
PSDS
P-protons (no. of)/nuclear charge
S-shielding(no. of)
D-distance from nucleus
S-strength of attraction
