Mrs Green - Section 1 Atomic Structure

Question 1

Define an isotope

Answer 1

Atoms of the same element with same number protons and different number of neutrons

Question 2

Why do isotopes react the same way

Answer 2

Because they have the same electronic configuration

Question 3

What’s the purpose of a mass spectrometer

Answer 3

Gives info about relative isotopic mass and relative abundance of isotopes

Question 4

What is the first stage of using the mass spectrometer

Answer 4

1. IONISATION
   Electrospray ionisation - sample dissolved in solvent and pushed thru nozzle at high voltage , each molecule gains a proton .

Electron impact ionisation - sample vaporised , electron gun used to fire high energy electrons at it, knocking an electron off each particle becoming 1+ ions.

Question 5

what’s the second stage of using a mass spectrometer machine

Answer 5

acceleration - positive ions accelerated by an electric field , ef gives same KE to all ions, lighter ions experience more acceleration than heavier

Question 6

what’s the third stage of using a mass spectrometer machine

Answer 6

ION DRIFT
ions drift thru a region with no EF , drift at the same speed they left the ef

Question 7

whats the 4th stage of using a mass spectrometer machine?

Answer 7

DETECTION
the detector detects the current created when the ions hit it

Question 8

What sub shells does 1st and 2nd shell contain

Answer 8

1s
2s and 2p

Question 9

What sub shells does the 3rd and 4th shell contain

Answer 9

3s 3p 3D
4s 4p 4d 4f

Question 10

What’s the maximum number of electrons the s, p, d ,f sub shells contain

Answer 10

2,6,10,14

Question 11

Define first ionisation energy

Answer 11

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

Question 12

Factors affecting ionisation energy

Answer 12

1 . Nuclear charge - more protons , more positively charged nucleus , stronger attraction for electrons
2. Distance from nucleus - closer electron to nucleus has a stronger attraction
3. Shielding - as shielding increases the outer electrons feel less attraction to the nucleus

Question 13

Second ionisation energy definition ?

Answer 13

The energy needed to remove an electron from each ion in one mole of gaseous 1+ ions to from one mole of gaseous 2+ ions

Question 14

A high ionisation energy means

Answer 14

There’s a high attraction between electron and nucleus

Question 15

Why does aluminium have a lower first ionisation energy than magnesium ?

Answer 15

Aluminium’s outer electron is in a 3p orbital rather than 3s like magnesium, the 3p orbital is in a slightly higher energy than the 3s so the electron is found further from the nucleus and takes less energy to overcome.
It’s distance and shielding that override the effect of nuclear charge

Question 16

Successive ionisation energy

Answer 16

The amount of energy needed to remove an electron one after the other

Question 17

Describe the ionisation trends down group 2

Answer 17

The extra shell added to each period decreases the electrostatic forces of attraction between the positive nucleus and negative outer electrons meaning it’s easier to remove the outer electrons resulting in lower ionisation energies .

Question 18

Why as you move across period 3 the ionisation trends sometimes decrease

Answer 18

Nuclear charge - as u move across the period it gets harder to remove the outer electrons because the number of protons increase meaning a stronger nuclear attraction

Question 19

Explain the drop in groups 5 and 6 due to electron repulsion

Answer 19

P - 3p3
S - 3p4

In phosphorus the electron is being removed from a single occupied orbital in sulfur it’s removed from an orbital containing 2 electrons , the repulsion between both electrons in the orbital means electrons are easier to remove from shared orbital

Question 20

Within each shell being removed successive ionisation energies increase because

Answer 20

Electrons are being removed from an increasingly positive ion meaning an increased attraction between the electrons and nucleus , they’re also getting closer to the nucleus and are held more strongly

(Take into account distance , nuclear charge )

Question 21

what were the 3 atom models

Answer 21

dalton described atoms as solid spheres
jj thomps discovered negative charged particles, positive plum, , plum pudding
rutherford fired alpha particles at thin sheet , few aplha particles deflected v strongly by nucleus.