Nuclear chemistry Flashcards

This is a branch of chemistry that is concerned with the study of the nucleus

1
Q

What is an nucleus made up of?

A

Protons

nutrons

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2
Q

What is an Isotope?

A

An isotope is an element that have the same number of protons ( protons never changes) but that have different number of neutons.

This changes the element’s atomic mass.

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3
Q

What is the mass number made up of? or atomic mass or relative isotopic mass?

A

Made up of protons and nutrons

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4
Q

What is the charge of a

Electron

Neutron

Protons

A
  1. Electron: -1.602 X 10 ^ -19
  2. Neutron: 0
  3. Protons: 1.602 X 10 ^19
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5
Q

what is the relative isotopic mass? And how is it measured ?

A
  1. a unit of comparison that compares the atomic mass of elements to carbon 12 atoms which has a mass of 12
  2. relative isotopic mass is also related to the atomic mass unit: 1 atomic mass unit or AMU = 1/12 (mass of carbon 12 atom)
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6
Q

How do we know if an atoms is stable or unstable? How can we tell what type of decay will occur

A
  1. If it is an isotope
  2. If too many neutrons: beta - decay
  3. too many protons : beta + decay
  4. Too many many protons ( more than 82): alpha decay
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7
Q

What are the two nuclear forces that are present in the atoms?

A
  1. Strong force:the force that bonds protons and nutrons
  2. Electromagnetic force: force that are created by the repulsion of positive harges
  3. However the nucleus is able to stay bond together because the strong forces is greatest than electromagnetic forves.
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8
Q

What is radioactive decay?

A

Unstable nuclei emit radiation in order to stabilize itself

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9
Q

What determines if the atom is stable? And what can make a nucleus unstable?

A
  1. The strong force determines how stable and atom is because it holds enough energy to keep the nuclei together ( protons and neutrons)
  2. if they have to many protons or too many neutrons for instance an isotope, these upset the strong forces.
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10
Q

How does an unstable nuclei tries to balance itself?

A

It does so by giving off either a proton or neutrons to make sure the strong force is holding the nucleus together, that is what creates radio active decay

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11
Q

What are the three types of decay?

A
  1. alpha decay
  2. Beta decay -
  3. Beta decay +
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12
Q

What is Alpha decay? what is an alpha particle made up off?

What is their mass and charge and what happens when an atoms looses and alpha particle?

A
  1. the loss of an alpha particle
  2. An alpha particle is made of two protons and two neutrons
  3. each alpha particle have a mass of 4 and a charge of +2

When it looses an alpha particle

  1. When an atom looses an alpha particle it looses a mass of 4 ( so their atomic number decrease by 4) and the atomic number ( the protons) decreases by 2
  2. Results: a new element is form that is two places lower in the periodic table of the element that loss the protons and neutrons.
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13
Q

what is beta negative decay?

A
  1. When an atom has too many neutron it can experience beta decay
  2. two protons and one neutrons leave
  3. however the neutrons changes itself into a protons and an electon
  4. The proton stays with the atom but the electon is lost
  5. when you loose electron it is at a high energy ( has the potential of getting closer to a proton)

Results of Beta decay

  1. As your atom gains a proton however it will increase the atomic mass of the particle ( which is made of protons) so the resulting element will have one place higher in the periodic table then the atoms that emitted the decay.
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14
Q

What is beta positive decay?

A
  1. When an atom has too much protons it goes through beta positive decay
  2. A proton is converted into a neutron and a positive beta particle called a positron

What are positrons?

  1. positrons have the same mass as an electron but have a positive charge

Results

  1. By loosing a protons but gaining a neutron the atomic mass increases by one but the atomic number decreses by 1
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15
Q

What is nuclear half-life

A
  1. How long it takes for the nuclear processes (number of protons and neutrons) change, to go through decay or
  2. the time that it takes for 1/2 of a substance to decay
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16
Q

whys is the half-life of an element 1st order decay?

A

because the half life of an atom is always constant, you will loose the same thing every tims..

17
Q

Explains the exponential decay?

A
  1. It is a graph that allows us to see the decay of 1/2 in exponent curve graphs going downwards
  2. Semi-log plot: allows you to plot the exponential decays in a lin e
    1. if the curve is up then the slope is +
    2. if the curve is down then the slope is -