Writing reactions for beta and alpha emitters?

Question

The following are beta emitters. Write the reactions produced in each case:

1. Carbon-14
2. Strontium-90
3. Potasium-40
4. Nitrogen-13

The following are alpha emitters. Write the reactions produced in each case:

1. Uranium-238
2. Thorium-230
3. Uranium-235
4. Radon-222

Polonium 214 decays when it loses an alpha particle. Write the nuclear equation.

Argon-39 decays to become Potassium-39. Write the nuclear equation.


If somebody could just explain to me how i'm supposed to find the answers for these then that would be great.

Answer 1

A beta-emitter loses an electron. this INCREASES atomic number by 1 but leaves mass number the same.

An alpha-emitter loses a helium nucleus, that's two protons and two neutrons; so atomic number goes down 2, and mass number down 4.

Balanced equations just need to show all the mass numbers and atomic numbers.

Examples:

Beta: Superscript3 subscript1 H ---> Superscript3 subscript2 He + superscript0 subscript-1 e

Alpha: Super226 Sub88 Ra (radium) ---> Super222 Sub86 Rn (radon) + Super4 Sub 2 He

Last example: Super39 Sub18 Ar ---> Super39 Sub19 K + Super? sub? [type of particle]. Fill in the ?? by balancing both total mass number and total charge.

NB: although it does not have zero mass, an electron has zero mass number because mass << 1 a.m.u.