Williamsburg High School for Architecture and Design

Mr. Quinn and Ms. Tom9/30/13

How do I balance natural decay equations?

4 = 2 + 2 Y = mx + b 14

6C → 147N + 0

-1e

XA

Z

Mass Number

Atomic NumberElement Symbol

Atomic number (Z) = number of protons in nucleus

Mass number (A) = number of protons + number of neutrons

= atomic number (Z) + number of neutrons

A

Z

1p1

1H1

or

proton

1n0

neutron

0e-1

0-1

or

electron

0e+1

0+1

or

positron

4He2

42

or

particle

1

1

1

0

0

-1

0

+1

4

2

23.1

Balancing Nuclear Equations

1. Conserve mass number (A).

The sum of protons plus neutrons in the products must equal the sum of protons plus neutrons in the reactants.

1n0

U23592

+ Cs13855

Rb9637

1n0

+ + 2

235 + 1 = 138 + 96 + 2x1

2. Conserve atomic number (Z) or nuclear charge.

The sum of nuclear charges in the products must equal the sum of nuclear charges in the reactants.

1n0

U235

92+ Cs

138

55Rb

96

37

1n0

+ + 2

92 + 0 = 55 + 37 + 2x0

Balancing Nuclear Equations

212Po decays by alpha emission. Write the balanced nuclear equation for the decay of 212Po.

4He2

42

oralpha particle -

212Po 4He + AX84 2 Z

212 = 4 + A A = 208

84 = 2 + Z Z = 82

212Po 4He + 208Pb84 2 82

23.1

How do I balance artificial transmutation

equations?

II. Nuclear Transmutations

•Nuclear reactions that are induced in a way that nucleus is struck by a neutron or by another nucleus (nuclear bombardment) a.Positive ion bombardment

- alpha particle is the most commonly used positive ion- uses acceleratorsExamples:14

7 N + 42 He → 17

8 O + 11 H

94 Be + 4

2 He → 126 C + 1

0n

Neutron bombardment- neutron is bombarded to a nucleus to form a new nucleus- most commonly used in the transmutation to form synthetic

isotopes because neutron are neutral, they are not repelled by nucleus

Example: 58

26 Fe + 10 n → 59

26 Fe → 5927 Co + 0

-1 e

II. Nuclear Transmutations

Transuranium elements

-Element with atomic numbers above 92-Produced using artificial transmutations, either by:

a. alpha bombardmentb. neutron bombardmentc. bombardment from other nucleiExamples:

a.

b.

4He2

Pu23994

+ Cm24296

1n0

+

1n0

U23892

+ U23992

0 e-1

Pu23994

+ Np23993

+ 0-1 e

14N7

U23892

+ Es24799

1n0

+ 5c.