unit: nuclear chemistry transmutations day 3 – notes

Unit: Nuclear Chemistry

Transmutations

Day 3 –

Notes

After today you will be able to…

• Identify and explain two ways in which transmutations can occur.• Balance nuclear reactions.

al∙che∙my [al-kuh-mee] noun:a science that was used in the Middle Ages with the goal of changing ordinary metals into gold

-Courtesy of Merriam-Webster (2015)

A brief history…• The modern practice of

chemistry started in medieval Europe and the Middle East.

• Alchemists (~16th century) believed that by doing certain chemical reactions, you could turn cheap metals into gold.

• We now know that no chemical reaction can achieve this goal.

However, through transmutations

modern chemists can change one element

into another.

Transmutation Reactions

Transmutation: The conversion of an atom of one element to an atom of another element.• Can occur in two ways:

1.Radioactive decay2.When the nucleus of an atom

is bombarded with certain types of particles (proton, alpha, etc.)

Transmutation Reactions

• Many transmutations occur in nature.– Example: C-14 is made

from N-14 in the upper atmosphere.

C146N14

7 n10+ p1

1+

Transmutation Reactions

• Many other transmutations are done in laboratories.– Example: The first artificial

transmutation was done by Rutherford (1919).

– Eventually led to the discovery of the proton.

F189N14

7 He

42+

Writing Transmutation Reactions

Transmutation reactions are written using the following guidelines:1.Make sure the sum of the

mass numbers (top left) is the same on both sides of the equation.

2.Make sure the sum of the atomic numbers (bottom left) is the same on both sides of the equation.

3. Be familiar with the following particles and their notations:

Particle Symbol

AlphaBeta

GammaNeutronProton

Positron

e0-1

γ00

He42

n10

H11

α42orβ0-1or

or p11

e0+1 β0+1or

Writing Transmutation Reactions

Example: Identify the missing information.

?24296Pu239

94 ?+ n10+H

e42 C

m

Writing Transmutation Reactions

Example: Identify the missing information.

Cf24698U238

92 + n10+12

6C?? 4

Writing Transmutation Reactions

Example: Write the beta decay for carbon-14.

e0-1 N14

7+146C

Writing Transmutation Reactions

Example: Write the alpha decay for radon-222.

He42 Po218

84+22286 R

n

Transuranium Elements

• Elements in the Periodic Table with atomic numbers above 92 are called transuranium elements.

• All of these elements undergo transmutation, do not occur in nature, and are synthesized in the laboratory.

• To synthesize these elements, particle accelerators bombard nuclei with fast moving particles.

Particle Accelerator:

Questions?Begin

WS3