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Flashcards in Particles Deck (56)
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1

Name parts of the atomic model

Protons
Neutrons
Electrons

2

Describe the atomic model

A dense nucleus containing protons and/or neutrons that has electrons orbiting around it in energy levels

3

Mass of a proton?

1.67 x 10^-27 (Kg)

4

Charge of a proton?

+1.60 x 10^-19 (C)

5

Charge of a neutron?

0

6

Mass of a neutron?

1.67 x 10^-27 (Kg)

7

Mass of an electron?

9.11 x 10 ^-31 (Kg)

8

Charge of an electron?

-1.60 x 10^-19 (C)

9

Relative charge and mass of an Electron?

Relative charge: -1
Relative mass: 0.0005

10

Relative charge and mass of an Proton

Relative charge: +1
Relative mass: 1

11

Relative charge and mass of an Neutron?

Relative charge: 0
Relative mass: 1

12

What is the atomic number?

Number of protons in an atoms nucleus

13

Significance of protons and electrons?

Protons define elements

Electrons define how they will react

14

What is the nucleon number?

The amount of protons and neutrons in an atom

Is also often the RELATIVE mass of an atom

15

Define an isotope?

An isotope is an atom with the same amount of protons but a different amount of neutrons

16

What effect does having different amounts of neutrons in an atom have?

No effect on the chemical properties of the atom,

however it will effect the stability of the atom and it may be radioactive and decay over time

17

Uses of an isotope?

Can be used to see how old an organism is

All living things have the same %age of carbon-14, as it decays when it dies carbon-14 decays into other elements

The amount of carbon-14 left can be used to deduct how old something has been dead for

18

What is specific charge?

The ratio of the particle's charge per unit mass

Given in CKg^-1

19

Equation for specific charge?



Specific charge = charge
---------------
mass

20

If the gravitational force is weaker than the electrostatic force in an atom, what holds it together?

The strong nuclear force

21

What is the strong nuclear force?

Holds atoms together

22

How does the strong nuclear force work?

If Nucleons are less than 0.5 femtometres apart they will be repulsive

Strong nuclear force has to be larger than electrostatic (electrostatic only occurs between protons so is repulsive) force

Between 0.5 and 3 femtometres the force is its most attractive

After 3 femtometres the force falls rapidly towards 0

23

Basic Features of the strong nuclear force?

Only works when nucleons are a few femtometres away

Strong Nuclear force must be stronger than electrostatic force for it to be stable and hold atom together

Strength of the strong nuclear force falls off quickly

Size of the force is equal between all nucleons

It can be repulsive when lower than 0.5 femtometres apart

24

When does alpha decay occur?

Only happens in very large unstable nuclei

25

What happens when an alpha particle is emmitted?

From the original particle the daughter particles nucleus' proton number decreases by 2 and the nucleon number decreases by 4 - and an alpha particle emitted

Essentially from the original particle releases a daughter particle and helium

26

What is Beta (minus)decay?
When does it happen?

It is when an electron and an anti-neutrino are emitted from the nucleus and a neutron turns into a proton

Occurs when there are too many more neutrons than protons

27

What happens when beta minus decay occurs?

An electron and an antineutrino are emitted from the nucleus of the atom, then a neutron turns into a proton

So from the original particle the proton number increases by 1 and the nucleon number stays the same

28

What happens when beta minus decay occurs?

An electron and an antineutrino are emitted from the nucleus of the atom, then a neutron turns into a proton

So from the orginal particle the proton number increases by 1 and the nucleon number stays the same

29

Why is there an antineutrino in beta minus decay?

Observations showed that there was less energy after the decay than before, and they originally thought it was just an electron emitted.

Due to conservation of energy another neutral charged and almost massless particle must also be emitted

25 years later Wolfgang Pauli's particle was discovered and named the neutrino

30

What is photon?

It is a packet of electromagnetic radiation