DN1). Atomic Structure Flashcards Preview

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Flashcards in DN1). Atomic Structure Deck (41):
1

Neutron

Rel charge, rel size, actual charge(C), actual size(kg)
0 , 1 , 0 , 1.675x10^-27

2

Electron

Rel charge, rel size, actual charge(C), actual size(kg)
-1 , 1/1836 , 1.602x10^-19 , 9.109x10^-31

3

Mass number

Protons + neutrons

4

Proton number

Number of protons or electrons

5

Atoms are....

Neutral
Equal number of protons and electrons

6

Ions are formed by....

Adding or removing electrons
(Negative if adding, positive if removing)

7

Isotopes are

Atoms with the same number of protons as each other but different number of neutrons

8

Physical properties of isotopes are...

Different

9

Chemical properties of isotopes are...

The same (electrons)

10

How to calculate RFM:

Mass of isotope x amount + mass of isotope x amount
---------------------------------------------------------------
Total amount

11

Relative atomic mass (Ar)

Weighted average mass of an atom of an element taking into account all the naturally occurring isotopes relative to 1/12 the relative atomic mass of an atom of carbon 12

12

Use of the time of flight mass spectrometer

Gives accurate information about RFM and isotopic abundance
Helps to identify elements and molecules

13

4 simple steps of a time of flight mass spectrometer

Electrospray ionisation
Acceleration
Ion drift
Detection

14

Electrospray ionisation

Beam of electrons fired at sample --> ionises sample by knocking out an electron
M(g) + e- ———> M+(g) + 2e- (Should happen)
M(g) + e- ———> M2+(g) + 3e- (can happen if electron too energetic)

15

Why is Electrospray ionisation used

Because it reduces the number of molecules that fragment

16

Acceleration

An electric field (negative) attracts the positive ions
The ions accelerate towards it
Some are discharged (if they hit the plate) but some escape through a hole in the plate = beam of positive ions
Ions with the same charge have the same kinetic energy and are travelling at the same speed

17

Ion drift

Ions entering have two variables (charge, z & mass, m)
Time taken = m/z mass charge ratio
Bigger number = longer time of flight

18

Detection

Time of flight detected by computer
Positive ions hits metal plate and pulls off an electron
This generates an electric current
More ions = bigger current , measured by detector

19

Br abundance

50% Br-79, 50% Br-81

20

Cl abundance

75% Cl-35, 25% Cl-37

21

Why are there often small peaks at m/z +1

Because of H-2 and C-13

22

Explain chlorine TOF

(Cl-35—Cl-35)+ 3/4 x 3/4 = 9/16
(Cl-37—Cl-35)+ 3/4 x 1/4 = 3/16 X2 as two ways round
(Cl-37—Cl-37)+ 1/4 x 1/4 = 1/16
So three peaks each separated by two units in the ration 9:6:1

23

RFM=

m/z

24

Relative atomic mass formula=

(Abundance x m/z) + (abundance x m/z)
----------------------------------------------
Abundance

25

Relative formula mass from TOF

m/z

26

Sub level s

Number of orbitals 1
Maximum number of electrons 2
Shape Spherical

27

Sub level p

Number of orbitals 3
Maximum number of electrons 6
Shape py, px & pz

28

Sub level d

Number of orbitals 5
Maximum number of electrons 10
Shape -

29

Sub level f

Number of orbitals 7
Maximum number of electrons 14
Shape -

30

The sequence orbitals fill up

1s 2s 2p 3s 3p 4s 3d

31

4s sub-shell

Fills before 3d
Empties before 3d

32

Special two which don't fill as u would expect

Chromium (4s1 3d5 as more stable)
Copper (4s1 3d10 as more stable)

33

Ionisation energy

This involves taking away the outer electron from an atom or ion

34

First ionisation energy

The enthalpy change for removing one more of electrons from one mole of their atoms in gaseous state

35

3 factors that influence ionisation energy

Nuclear charge
Distance of outer electron from nucleus
Shielding

36

Down a group ionisation energy......

Decreases

37

Ionisation energy across a period...

Increases

38

Special phrase

Which is higher in energy therefore electron is easier to remove

39

Proton

Rel charge, rel size, actual charge(C), actual size(kg)
+1 , 1 , 1.602x10^-19 , 1.673x10^-27

40

first ionisation equation

X(g) -----> X(g)^+ + e^-

41

second ionisation equation

X^+ ------> X^2+ + e^- (all with state symbol g)