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Chemistry Content > Atomic Structure > Flashcards

Atomic Structure Flashcards

1
Q

Timeline of model of the atom

A
  • Democritus
  • John Dalton
  • J.J Thompson
  • Rutherford
  • Neils Bohr
  • James Chadwick
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2
Q

Democritus

A
  • Greek philosopher
  • atomos = indivisible
  • atoms could not be split
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3
Q

John Dalton

A
  • came up with atomic theory
  • all matter composed of atoms
  • they are indivisible and indestructible building blocks
  • represented atoms as hard spheres that couldn’t be split
  • atoms of an element were identical
  • different elements had atoms of different size and mass
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4
Q

J.J Thompson

A
  • atoms were indivisible
  • discovered atoms contained negatively charged particles (electrons)
  • put forward plum pudding model
  • atoms were spheres of positive charge with negative electrons randomly embedded throughout
  • realised when discovering electrons that atoms could not be solid spheres and could be broken down into smaller subatomic particles
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5
Q

Rutherford

A
  • gold foil experiment proves that plum pudding model was incorrect
  • fired positively charges alpha particles through gold foil
  • proved that atoms have their positive charge concentrated in a very tiny volume and that most of the atom was completely empty space
  • if the plum pudding model correct, then most of the alpha particles fired at the gold foil would be deflected, but most passed straight through
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6
Q

Niels Bohr

A
  • if electrons were a ‘cloud’ around the nucleus then it would spiral sown into the he nucleus causing it to collapse
  • thus Bohr proposed a new theory:
    • electrons can only exist in fixed orbits/shells
    • each shell has a fixed energy
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7
Q

Niels Bohr revised model

A
  • scientists discovered that not all electrons in the same shell had the same energy
  • meant somehow the previous Bohr model wrong
  • refined to add sub-shells/orbitals
  • Bohr believed each shell can only hold a fixed number of electrons
  • also, elements reactivity is due to its electrons, so when the shell is full, it is inert.
  • modified Bohr model includes the idea of sub shells and orbitals and we still use this model to explain basic ideas about bonding
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8
Q

James Chadwick

A
  • devised an experiment to prove the existence of neutrons
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9
Q

Different sub-atomic particles

A
  • nucleons = protons + neutrons

- electrons

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10
Q

Properties of subatomic particles

  • proton
  • neutron
  • electron
A
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11
Q

Isotopes

A
  • Atoms with the same number of protons and electrons but different number of neutrons
  • They have the same atomic number but a different mass number
  • the reactivity of isotopes are identical as they have the same number of electrons
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12
Q

Atomic number

A

The number of protons

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13
Q

Mass number

A

Total number of protons an neutrons

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14
Q

What affects the reactivity of an element

A

The number of electrons

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15
Q

Equation for RAM

A

Ar = sum of the abundance x atomic number / total number of abundance

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16
Q

Relative atomic mass (RAM) (Ar)

A

The relative atomic mass is the average mass of its atoms compared to 1/12 the mass of a carbon-12 atom

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17
Q

Calculate the abundance of the different Chlorine molecules

A
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18
Q

Different stages of TOF

A
  1. Ionisation
  2. Acceleration
  3. Flight Tube (Ion drift)
  4. Detection
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19
Q

Stage 1 Ionisation for elements and low Mr compounds

A
  • for ionisation to colour it has to be a gas
  • high energy electron are fired by an electron gun
  • this knocks out an electron of each particle
  • the particle becomes a positive ion
20
Q

Stage 1 Ionisation for high Mr compounds

A
  • ionisation is in an aqueous solution (sample in a volatile solvent)
  • passed through a hypodermic needle attached to positive terminal of high voltage power supply
  • the particle gains a proton
21
Q

Equation for Stage 1 elements and low Mr

A
22
Q

equation for stage 1 ionisation with high Mr compounds

A
23
Q

Stage 2 acceleration

A
  • the positive ions are accelerated by using an electric field
  • the ions are accelerate so that they have the same kinetic energy
24
Q

Stage 3 flight tube (ion drift)

A
  • particles have the same kinetic energy

- ions with a smaller mass will travel faster along the tube

25
Q

Stage 4 detection (3 marks)

A
  • positive ions hit the negative plate and produce and electric current
  • the electrons move from the plate to the ion
  • the size of current is proportional to the number of ions
26
Q

Equations for TOF

A 
KE = 1/2mv^2
t = d/v
27
Q

Two types of ionisation

A 
Electron impact (gun)
Electrospray (needle)
28
Q

How to calculate the mass of an ion

A

1 mole of Mass of element/1000 to get into kg

Then ANS/6.022x10^23 To get mass of 1 ion in kg

29
Q

What is a species

A
  • atom or molecules
30
Q

Why is there a small peak at the Mr+1

A
31
Q

What are the different orbitals?

A

s, p, d, f

32
Q

How many electrons can an s orbital hold

A

2

33
Q

How many electrons can a p orbital hold

A

6

34
Q

How many electrons can be held on a d orbital

A

10

35
Q

Electronic configuration of Chromium

A

[Ar} 4s1 3d5

Not [Ar] 4s2 3d4

36
Q

Electronic Configuration of copper

A

[Ar] 4s1 3d10

Not [Ar] 4s2 3d9

37
Q

What is the first ionisation energy

A
  • this is the energy needed to remove one mole of electrons from
  • one mole of atoms in their gaseous state
  • to form one mole of 1+ ions (also in their gaseous state)
38
Q

Ionisation energy down a group

A
  • ionisation energy decreases
  • atomic radius increases
  • more shells/shielding
  • weaker attraction between nucleus and OUTER electron
39
Q

Equation for first ionisation, second ionisation energy…

A
40
Q

General trend of ionisation energy across a period

A
  • increases
  • smaller atomic radius
  • more protons
  • stronger forces of attraction between nucleus and OUTER electron
  • same shielding/ same shells
41
Q

Why does going from group two to three dip in ionisation energy

A
  • going to a different sub shell, eg 2s to 2p and p is a higher energy than s
  • the distance is further away
  • so the forces of attraction is weaker between nucleus and electron
  • less energy required to remove the electron
42
Q

Why does it dip from group 5 to group 6 in ionisation energy

A
  • there is an electron pair repulsion
  • p e- from orbital with one e-
  • s e- from orbital with two e-
  • there is more electron electron repulsion in s
43
Q

Successive ionisation energy

A
  • atoms with more than one electron can have them successfully removed
44
Q

Second ionisation energy

A
  • the energy required to remove one mole of electrons
  • from one mole of gaseous unipostive ions
  • to form one mole of gaseous dispositive ions
45
Q

Trend of successive ionisation energy

A
  • increases as the electron is being pulled away from a more positive species

A large increase occurs when there is a change of shell because there is a big decrease in shielding - large increases can be used to predict the group of an unknown element

46
Q

What does it mean if there is a really big number jump in successive ionisation energy

A

This shows which group the element is in

Chemistry Content (31 decks)

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