Stable and unstable nuclei

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Created by: EMBurridge
Created on: 18-01-15 12:58

Which 3 forces are present in the nucleus of an atom?

Electromagnetic force, gravitational force and strong nuclear force.

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What is the electromagnetic force?

A force that causes the protons in the nucleus to repel each other.

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What is the gravitational force?

A force that cause all the nucleons (protons and neutrons) to attract due to there mass.

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What is the strong nuclear force?

The electromagnetic force is much, much stronger than the gravitational force. In order to prevent the nucleus from falling apart, the strong nuclear force overcomes the strength of the repulsive electromagnetic force and holds the nucleus together.

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What is the range for the electromagnetic force and the strong nuclear force?

Electromagnetic repulsive force extends over a much larger range than the strong interaction that it is considered infinite. The strong interaction only holds nucleons together at very small separation (a few femtometres-the size of the nucleus)

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Describe how the strong nuclear and electromagnetic (EM) forces vary with nucleon separation. (1 fm = 1x10ˉ¹⁵m)

Strong nuclear force is repulsive for separations smaller than 0.5fm. Between 3-4fm the strong nuclear force is most attractive, after 4fm it's attraction rapidly falls to zero. EM force is strongest at small nucleon separations but is infinite.

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What happens when a nucleus is unstable?

It emits radiation-in the form of alpha(α) decay or beta(βˉ) decay.

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Describe alpha decay.

Alpha decay is the emission of 2 protons and 2 neutrons from the nucleus of an atom. In other words the emission of a helium nucleus.

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Describe beta decay.

Beta decay is the emission of a high speed electron and an antineutrino due to the 'neutron rich' nucleus turning a neutron into a proton.

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Using an equation, show the decay of Uranium by alpha emission.

²³⁸₉₂U -------> ²³⁶₉₀Th + ⁴₂α

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Using an equation, show the decay of Rhenium by beta emission.

¹⁸⁷₇₅ Re -------> ¹⁸⁷₇₆Os + ⁰ ₋ β + ṽ

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Other cards in this set

Card 2

Front

What is the electromagnetic force?

Back

A force that causes the protons in the nucleus to repel each other.

Card 3

Front

What is the gravitational force?

Back

Card 4

Front

What is the strong nuclear force?

Back

Card 5

Front

What is the range for the electromagnetic force and the strong nuclear force?

Back

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Stable and unstable nuclei