3 Types of Nuclear Emission

3 types:

• alpha $\alpha$ particles
• beta $\beta$ particles
• gamma $\gamma$ rays

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ionisation → refers to ability to eject electrons from atoms to form ions. since atoms lose electrons → number of protons > number of electrons.

• thus ions carry charge

Nuclear Emission	Nature	Relative ionising Effect	Relative Penetrating Ability
	an $\alpha$ particle → consists of 2 protons and 2 neutrons tightly bound together. identical to helium nucleus	highest	- least - easily absorbed by piece of paper, thin aluminium foil, human skin
	a $\beta$ particle is a fast moving electron ejected from a radioactive nucleus.	medium	- medium - they are absorbed by piece of aluminium that is few mm thick
	a $\gamma$ ray is electromagnetic radiation emitted by radioactive nucleus with excess energy	lowest	- highest - pass through most materials easily. they are absorbed by lead that is a few cm thick or very thick concrete.

nuclei of same isotope will emit same type of nuclear radiation. during $\alpha$-decay or $\beta$-decay → nucleus changes to that of diff. element

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Alpha Decay

when a nucleus undergoes $\alpha$-decay:

• emits an $\alpha$ particle (identical to helium nucleus ${}_2^{4}He$ )
• nucleon number decreases by 4 and proton number decreases by 2

we can use equation involving nuclide notation to represent changes in composition of nucleus. known as nuclide equation. e.g. for radium (Ra) emits $\alpha$ particle → it decays to radon (Rn) ${}_{88}^{226}Ra{\to }_{86}^{226}Rn{+}_2^{4}He$

arrow means → react to form. total number of nucleons and protons before and after reaction is same

Nucleon numbers: 226 → 222 + 4 Proton numbers: 88 → 86 + 2

total relative charge before and after nuclear emission should be same

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Beta Decay

when nucleus undergoes $\beta$ decay:

• it emits a $\beta$ particle (an electron)
• nucleon number remains same and proton number increases by one

e.g. carbon-14 (radioactive carbon C) emits an $\beta$ particle (electron) it decays to nitrogen (N)

${}_6^{14}C{\to }_7^{14}N{+}_{-1}^{0}e$

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Gamma Radiation

often when nuclei undergo alpha decay or beta decay → gamma radiation is also emitted.

e.g. when uranium emits alpha particle → it decays to form Thorium and 2 gamma rays of diff. energies are emitted

${}_{92}^{238}U{\to }_{90}^{234}Th{+}_2^{4}He+2_0^0\gamma$

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