Atomic Structure Flashcards

1
Q

Define isotope

A

isotopes are atoms of the same element with different numbers of neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What decides the chemical properties of an element? And how does this effect isotopes

A

number and arrangement of electrons decides the chemical properties

isotopes have the same configuration of electrons so they have the same chemical properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why do isotopes of an element have slightly different physical properties?

A

physical properties tend to depend on the mass of the atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

19th century: What did John Dalton say atoms were?

A

Solid spheres
Different spheres made different elements
(All atoms of an element = same mass)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

1897: What did J.J. Thomson discover and what did it show?

A

Discovered the electron
Showed atoms weren’t solid
(Model known as ‘plum pudding model’)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

1909 - Ernest Rutherford: What did he find out?

A

Conducted the golden foil experiment:

Fired positively charged alpha particles at a very thin sheet of gold
Particles passed straight through gold & only small no. of particles were deflected backwards (pulm pudding model said = alpha particles would be deflected by the positive ‘pudding’ in atom)
= developed into nuclear model of atom
Tiny positive nucleus surrounded by ‘cloud’ of negative electrons - most of atom is empty space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What was Niels Bohr’s model & discovery?

A

Model: where electrons exist in shells or orbits of fixed energy
Discovered: When electrons move between shells, electromagnetic radiation (with fixed energy or frequency) is emitted/absorbed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What have modern day scientists discovered & so what did they do?

A

Electrons in same shell ≠ same energy
Bohr model = wrong ∴ they refined it & added sub-shells
(Isn’t perfect model but it’s simple and explains many experimental observations e.g. bonding & ionisation energy trends)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Define relative atomic mass

A

the average mass of an atom compared to 1/12 mass of an atom of C12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define relative molecular mass

A

the average mass of a molecule compared to 1/12 mass of an atom of C12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Relative masses can be measured by using a ____ ____________

A

mass spectrometer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Step 1 is ______ and the 2 ways of doing this

A

ionisation

electrospray ionisation

electron impact ionisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe electrospray ionisation

A

The sample is dissolved and pushed through a small nozzle at high pressure. A high voltage is applied to it, causing each particle to gain a H+ ion. The sample is turned into a gas made up of positive ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe electron impact ionisation

A

The sample is vaporised and an ‘electron gun’ is used to fire high energy electrons at it. This knocks one electron off each particles so they become +1 ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Step 2 of mass spec is _____

A

Acceleration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe acceleration

A

The positively charged ions are accelerated by an electric field so that they all have the same kinetic energy. ( This means that the lighter ions will move faster than the heavier ones)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Step 3 of mass spec is _____

A

ion drift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe ion drift

A

The ions enter a region with no electric field, so they just drift through it. Lighter ions will drift through faster than the heavier ones.

19
Q

Step 4 of mass spec is _____

A

detection

20
Q

Describe detection

A

because lighter ions travel at high speeds in the drift region, they reach the detector in less time than the heavier ones. The detector detects charged particles and a mass spectrum is produced.

21
Q

A mass spectrum is _____/______ plotted against _________

A

mass/charge

abundance

22
Q

Equation for calculating RAM when analysing spectra

A

RAM = m/z x abundance
____________________
total abundance

23
Q

If the relative abundance is not given in percentage when calculating RAM you need to…

A

divide answer by 100

24
Q

Elements with different _____ produce more than one line in a mass spectrum because the ______ have different masses.

A

isotopes

25
Q

A molecular ion, M+, is formed in the mass spectrometer when one electron is removed from the molecule. This gives a peak in the spectrum with a mass/charge ratio equal to ________ ________ ____ of the molecule. This can be used to help identify the unknown compound.

A

relative molecular mass

26
Q

Electron shells are made up of ___-______ and ________

A

sub-shells

orbitals

27
Q

sub shell s p d

number
of 1 3 5
orbitals

Max 2 ? ?
electrons

A

6

10

28
Q
  1. electrons fill up the ______ energy level first
  2. electrons fill orbitals ________ first before they start sharing.
A
  1. lowest
  2. singly
29
Q

electron configuration of copper ?

A

1s2 2s2 2p6 3s2 3p6 4s2 3d9

30
Q

electron configuration of chlorine using noble gas?

A

[Ne] 3s2 3p5

31
Q

Define Pauli exclusion principle

A

Each orbital can hold a maximum of TWO electrons - must have opposite spins

32
Q

Define Hunds rule

A

When filling the orbitals of a sub level, put one electron in each orbital before pairing them

33
Q

Define Aufbau principle

A

lower energy levels fill before higher energy orbitals

34
Q

Define first ionisation energy

A

energy needed to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions

35
Q

Show the first ionisation energy of Na

A

Na(g) –> Na+(g) + e -

36
Q

ionisation depends on 3 things

describe each
shielding
distance from nucleus
nuclear charge

A

more energy levels = less attraction

attraction decreases with distance

more protons in the nucleus = more positively charged the nucleus is = stronger the attraction for the electrons

37
Q

A high ionisation energy means there’s a high ___________ between the electron and the nucleus and so more ______ is needed to remove the electron.

A

attraction

energy

38
Q

Define second ionisation energy

A

the energy needed to remove 1 electron from each ion in 1 mole of gaseous +1 ions to form 1 mole of gaseous ions with a +2 charge

39
Q

Show second ionisation energy of oxygen

A

O+(g) –> O2+(g) + e -

40
Q

Why is there 2 dips in the graph showing period 3 elements first ionisation energy?

A

dips on 3rd element and 6th element
3rd = change from s to p
6th = electron has paired to p orbital so it repels

41
Q

first ionisation energies of elements down a group ________

A

decrease

42
Q

first ionisation energies of elements across a period generally _______

A

increase

43
Q

Ionisation energy ________ down group 2

A

decreases

extra inner shells to shield and extra shell means that the outer electrons are further away meaning less attraction to the nucleus so less attraction

resulting in a lower ionisation energy

44
Q

ionisation energy _______ across a period

A

increases

number of protons is increasing, which means a stronger nuclear attraction