Unit 3

Question 1

What constitutes an alpha particle?

Answer 1

A helium nucleus (two protons, two neutrons)

Question 2

What does the term quantisation mean?

Answer 2

Can only have abrupt, discrete values

Question 3

Can an electromagnetic field direct a neutron?

Answer 3

A neutron cannot be deflected by and electromagnetic field as it has no charge

Question 4

What is a cathode ray?

Answer 4

A beam of electrons

Question 5

What is an isotope?

Answer 5

An element with the same atomic number (proton#) but different mass number(protons+ neutrons) so it has a different amount of neutrons

Question 6

Equation for speed of light?

Answer 6

Frequency X Wavelength

Question 7

Energy=

Answer 7

frequency X Plancks

Question 8

Energy (using wavelength)=

Answer 8

Speed of light X plancks/ wavelength

Question 9

What governs chemical properties of an element? Atomic number or atomic mass?

Answer 9

The atomic number. The protons govern its properties. This is why isotopes have many of the same properties, despite different #neutrons

Question 10

What do isotopes of an element have in common?

Answer 10

Number of protons

Question 11

What is the anti-particle counterpart of the electron?

Answer 11

The positron

Question 12

Geiger and Marsden directed a beam of alpha particles at metal foil, the fact that they deflected means what?

Answer 12

That there was a dense centre of positive charge.

Question 13

What is Einsteins equation?

Answer 13

E=m x c ²

Question 14

What did Dalton think Atoms were distinguished by?

Answer 14

Weight

Question 15

What do magnets do to the path of electrons?

Answer 15

Make them move in a curved path

Question 16

What did Millikans oil drop experiment show?

Answer 16

Charges on drops of oil were always a whole number multiple of -1.6x10-19 . (charge of an electron)

Question 17

What does speed of light =

Answer 17

frequency X wavelength

Question 18

E=

Answer 18

h X f

Question 19

What does quantised mean?

Answer 19

Comes in well defined quantities. Values are abrupt

Question 20

What must match for electrons to be promoted?

Answer 20

the energy difference between energy levels must be the same as the incoming energy

Question 21

What is mass defect?

Answer 21

it is the fact that the mass of individual protons neutrons… weigh less than the experimentally found mass of the atom

Question 22

Why is there a mass defect?

Answer 22

Some energy must be used in order to keep protons and neutrons separate

Question 23

How was the proton discovered?

Answer 23

Fired a particles at gold foil and found some had large deflection angles which meant that there was a dense centre of positive charge

Question 24

How was the neutron discovered

Answer 24

fired a particles at beryllium nothing was detected but when a block of paraffin was placed between the beryllium and the detector particles were detected.
Neutrons have no charge but could knock out other particles

Question 25

How do you work out average mass of isotopes?

Answer 25

(mass# X proportion/100) + (mass# X proportion/100)

Question 26

On periodic table what does period show?

Answer 26

The number of shells (energy levels)

Question 27

on periodic table what does group show?

Answer 27

Number of valence electrons