Chapter 1 - Atomic Structure

Question 1

What is the nucleus of an atom made up of?

What orbits the nucleus in shells?

Answer 1

Protons and Neutrons

Electrons

Question 2

What is the mass number?

What is the Proton Number?

Answer 2

The mass of an element, Neutrons + Protons only

The amount of Protons which is equal to amount of Electrons

Question 3

What are ions?

What are isotopes

What determines the chemical property of an element

Answer 3

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

Question 4

Elucidate the History of the Atom

Answer 4

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

Question 5

Elucidate the History of the Atom

Answer 5

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

Question 6

What is emitted when an electron moves between shells?

Answer 6

Fixed amount of electromagnetic radiation

Question 7

What is Relative Isotopic Mass?

Answer 7

Mass of an Isotope relative to 1/12 of Carbon-12

Question 8

What is Relative Molecular Mass?

Answer 8

Mass of a molecule relative to 1/12 of Carbon-12

Question 9

What is Relative Atomic Mass?

Answer 9

Mass of an element compared to 1/12 of Carbon-12, taking in account its Isotopes

Question 10

What is the formula for Isotopic Mass?

Answer 10

(xAB1 + yAB2)/AB1 + AB2

Question 11

Define abundance?

Answer 11

How common an isotope of an element is

Question 12

What is mass Spectrometry?

Answer 12

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

Question 13

Mass Spectrometry process?

Answer 13

1. Sample Heated and Vaporized
2. Ionization (to accelerate atoms and produce current)
3. Acceleration, positive ions attracted to a negatively charged plate, where all ions gain the same KE
4. Ion Drift, ions travelling at different speeds due to different mass
5. Detection, Ions hit another negatively charged plate where they get discharged and produce current and time of flight used by the machine

Question 14

What is Relative Formula Mass?(Mr)

What is the Formula for Atomic Mass (Ar)

Answer 14

The Mr is the total mass of an element/compound

Relative Atomic Mass = (Abundance x Isotope Mass) / 100

Question 15

What does the Mass Spectra show?

How does a mass spectra of diatomic molecules differ?

Answer 15

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

Question 16

What are the TOF Spectrometry equations?

Answer 16

KE = 1/2mv^2
Which can substituted into
V = D/t

Question 17

What is Avogadro’s Constant?

Answer 17

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

Question 18

How can you calculate the mass of an ion (kg)?

Answer 18

(Relative Isotopic Mass x 10^-3)/6.022*10^23

Question 19

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?

Answer 19

Va =Sqr rt (Mb*Vb^2/Ma)

Ta = Sqr rt (Tb^2*Ma/Mb)

Ma = Mb*Vb^2/Va^2

Question 20

What are electron shells/energy levels made up off?

Answer 20

Subshells and Orbitals

Question 21

How can we work out the amount of electrons in an energy level (n)

Answer 21

2n^2 (n = Quantum number, shell number)

Question 22

How much Orbitals does the SPDF subshells have?

How many electrons does each orbital have?

Answer 22

1, 3, 5, 7

2 electrons

Question 23

What is an Orbital?

What is the chance of finding electrons in an Orbital

Answer 23

A region where a pair of electrons with opposite spins moves in

95%

Question 24

What is electron spin?

Answer 24

Motion of the 2 electrons having opposite spin

Question 25

What does 1s^2 2s^2 sp^6 3s^2 mean

Hint: What does 1/2/3 mean, s/p mean/ exponents mean?

Answer 25

Number corresponds to Quantum Number, SubShell. Letters corresponds to the Orbital. Exponent represents electrons in that orbital

Question 26

What comes after 3p^6

Answer 26

4s^23d^104p^6, due to 4s^2 having lower energy level than 3d^10

Question 27

How do we create electronic configurations?

How do we do electronic configurations of Ions?

Answer 27

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

Question 28

How many subshells and electrons does the first 4 subshells have?

Answer 28

1st: S subshell. 2 electrons
2nd: SP subshells, 8 electrons
3rd: SPD subshells, 18 electrons
4th: SDPF subshells, 32 electrons

Question 29

How does the electronic configuration of Cr and Cu differ?

Answer 29

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

Question 30

Define 1st Ionization Energy

Define 2nd Ionization Energy

Answer 30

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

Question 31

What are the factors that affect IE?

Answer 31

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

Question 32

How does IE change between electrons and shells?

Answer 32

IE increases by a constant for each electrons in the same energy level until it moves to the next shell where IE dramatically increases