Nuclear Decay

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Conservation of charge – Sum of atomic numbers must be equal for both sides.
Conservation of mass number – Sum of mass numbers must be equal for both sides.

Particle	Atomic Number	Mass Number	Symbol
Alpha particle	2	4	[katex]_2^4He[/katex]
Anti-neutrino	0	0	[katex]\overline\nu[/katex]
Beta particle (electron)	-1	0	[katex]_{-1}^0e[/katex]
Deuteron (deuterium nucleus)	1	2	[katex]_1^2H[/katex]
Gamma ray	0	0	[katex]\gamma[/katex]
Neutron	0	1	[katex]_0^1n[/katex]
Neutrino	0	0	[katex]\nu[/katex]
Positron	1	0	[katex]_{+1}^0e[/katex]
Proton	1	1	[katex]_1^1H[/katex]

Types of Decay

Alpha	Beta Minus	Gamma
[katex]^A_Z \text X \rightarrow ^{A-4}_{Z-2} \text X + ^4_2 \text{He}[/katex] Emits alpha particle	[katex]^A_Z \text X \rightarrow ^{\space \space \space \space \space A}_{Z+1} \text X + {}^{\space \space \space 0}_{-1} e \space + ^0_0 \overline{\nu}[/katex] Emits electron* and antineutrino**	[katex]^A_Z X^* \rightarrow {}^A_ZX + \gamma[/katex] Emits gamma ray
A few cm of air Absorption	Around 1m of air Absorption	Many cm of lead Absorption
Strong Ionising Power	Medium Ionising Power	Weak Ionising Power

To conserve mass-energy, the mass deficit transforms to kinetic energy in expelled particles.

*An electron is emitted in beta minus decay, while an anti-electron (positron) is emitted in beta plus decay.

**In beta minus decay, a neutrino is emitted.