Chapter 1 - Atomic Structure Flashcards
What is the nucleus of an atom made up of?
What orbits the nucleus in shells?
Protons and Neutrons
Electrons
What is the mass number?
What is the Proton Number?
The mass of an element, Neutrons + Protons only
The amount of Protons which is equal to amount of Electrons
What are ions?
What are isotopes
What determines the chemical property of an element
An element with a charge, due to lost/gain in electrons or protons
An element with a different mass due to change in Neutrons
Electron arrangement, so all isotopes react the same whereas ions react differently
Elucidate the History of the Atom
John Dalton in 18th century described atoms as indestructible solid spheres. 1897, JJ Thompson deducted the ‘Plum Pudding Model’ representing electrons in fixed positions embedded in a cloud of positivity. 1909, Rutherford ‘Gold Foil Experiment’ representing a positively charged nucleus in the centre with electrons known as the nuclear model. 1911, Nelson Bohr further examined the nuclear model and created the atomic model where electrons orbit in shells. 1932, Chadwick discovered neutrons in the nucleus of an atom
Elucidate the History of the Atom
John Dalton in 18th century described atoms as indestructible solid spheres. 1897, JJ Thompson deducted the ‘Plum Pudding Model’ representing electrons in fixed positions embedded in a cloud of positivity. 1909, Rutherford ‘Gold Foil Experiment’ creating the Atomic Model, a positively charged nucleus in the center with electrons around it in empty space. 1913, Niels Bohr ‘Nuclear Model’ showing electrons orbiting in shells. 1932, Chadwick discovered the Nuetrons
What is emitted when an electron moves between shells?
Fixed amount of electromagnetic radiation
What is Relative Isotopic Mass?
Mass of an Isotope relative to 1/12 of Carbon-12
What is Relative Molecular Mass?
Mass of a molecule relative to 1/12 of Carbon-12
What is Relative Atomic Mass?
Mass of an element compared to 1/12 of Carbon-12, taking in account its Isotopes
What is the formula for Isotopic Mass?
(xAB1 + yAB2)/AB1 + AB2
Define abundance?
How common an isotope of an element is
What is mass Spectrometry?
Experiment that uses current produced from an isotopes in sample to calculate the abundance and the time of flight to calculate mass, made as a m/z ratio and plotted on a Mass Spectrum
Mass Spectrometry process?
- Sample Heated and Vaporized
- Ionization (to accelerate atoms and produce current)
- Acceleration, positive ions attracted to a negatively charged plate, where all ions gain the same KE
- Ion Drift, ions travelling at different speeds due to different mass
- Detection, Ions hit another negatively charged plate where they get discharged and produce current and time of flight used by the machine
What is Relative Formula Mass?(Mr)
What is the Formula for Atomic Mass (Ar)
The Mr is the total mass of an element/compound
Relative Atomic Mass = (Abundance x Isotope Mass) / 100
What does the Mass Spectra show?
How does a mass spectra of diatomic molecules differ?
The results from mass spectrometry. Which you can find the Ar of an element from
Peaks on mass spectra show different combinations of diatomic isotopes that create that m/z, as diatomic molecules defragment. E.g. 35Cl:37Cl in the ratio 3:1 when defragmented. 25% abundance is formed when 35Cl-35Cl, 37Cl-37Cl Molecules are formed and 50% when 35Cl-37Cl, 37Cl:35Cl is formed
What are the TOF Spectrometry equations?
KE = 1/2mv^2
Which can substituted into
V = D/t
What is Avogadro’s Constant?
6.022* 10^23, the number of atoms/molecules in one mole of a substance. E.g. 12g of Carbon-12 is 1 mole of Carbon-12 which will have 1(6.022*10^23) atoms of Carbon-12 in 12g of it
1 mole is equal to the ar expressed in grams
How can you calculate the mass of an ion (kg)?
(Relative Isotopic Mass x 10^-3)/6.022*10^23
How can we calculate the Velocity of Isotope A?
How can we calculate the TOF of Isotope A?
How can we calculate the Mass of Isotope A?
Va =Sqr rt (Mb*Vb^2/Ma)
Ta = Sqr rt (Tb^2*Ma/Mb)
Ma = Mb*Vb^2/Va^2
What are electron shells/energy levels made up off?
Subshells and Orbitals
How can we work out the amount of electrons in an energy level (n)
2n^2 (n = Quantum number, shell number)
How much Orbitals does the SPDF subshells have?
How many electrons does each orbital have?
1, 3, 5, 7
2 electrons
What is an Orbital?
What is the chance of finding electrons in an Orbital
A region where a pair of electrons with opposite spins moves in
95%
What is electron spin?
Motion of the 2 electrons having opposite spin
What does 1s^2 2s^2 sp^6 3s^2 mean
Hint: What does 1/2/3 mean, s/p mean/ exponents mean?
Number corresponds to Quantum Number, SubShell. Letters corresponds to the Orbital. Exponent represents electrons in that orbital
What comes after 3p^6
4s^23d^104p^6, due to 4s^2 having lower energy level than 3d^10
How do we create electronic configurations?
How do we do electronic configurations of Ions?
Half fill the boxes until each orbital contains 1 electron then refill and move onto the next subshell
Create electronic configuration as if it was a non-ion then remove/add the extra charge is has, 4s^2 removes its electrons before 3d^10 subshell
How many subshells and electrons does the first 4 subshells have?
1st: S subshell. 2 electrons
2nd: SP subshells, 8 electrons
3rd: SPD subshells, 18 electrons
4th: SDPF subshells, 32 electrons
How does the electronic configuration of Cr and Cu differ?
They promote 1 electron from their 4s subshell to their 3d subshell as it makes them more stable as its done to avoid repulsion in the 4s subshell
Define 1st Ionization Energy
Define 2nd Ionization Energy
Amount of energy to remove an electron from each atoms of 1 mole of gaseous atoms to form 1 mole of gaseous ions. O > O^+ + e
Amount of energy to remove a second electron from each ion of 1 mole of gaseous ions to form 1 mole of gaseous ions. O^+ > O^2+ + e
What are the factors that affect IE?
Charge of the Nucleus - Charge across periods as there’s more protons = increase IE as there’s more Nuclear Force on outer electrons, harder to loose them
Distance from Nucleus - Distance increases descending a group as atoms get bigger = Decrease IE as Nuclear Force weakens
Shielding - Shielding from previous shells, increases descending a group. Protects outer electrons from Nuclear Force. Shielding Increase = Decrease IE
Repulsion - In Orbitals if there’s spin they repel each other decreasing IE
How does IE change between electrons and shells?
IE increases by a constant for each electrons in the same energy level until it moves to the next shell where IE dramatically increases
