UNIT 2NUCLEAR REACTIONS

7.4 What are natural and artificial transmutations?May 19, 2010

DO NOW:1. What subatomic particle is negatively charged?

2. Write the nuclear decay equation for gold‐198.

3. If 1/8 of C‐14 is left over, how many half‐lives did the sample undergo

Electron (e-)

198 0 198

79Au -1β + 80Hg

AIM: What is the difference between artificial and natural transmutations

½ x ½ x ½ = 1/8, so 3 half lives

• Spontaneous Decay is when an unstable radioactive nuclei changes into a stable isotope.

• Every decay reaction we looked at so far represents spontaneous decay

REVIEW

TRY

Write the spontaneous decay reaction for:• 1. K 42‐

• 2. Radon 222‐

NATURAL AND ARTIFICIAL TRANSMUTATION

• ______________________ is a reaction in which we change one element to _________________element.

• • There are two kinds of transmutation reactions:

1. __________________________________2. __________________________________

Transmutation

different

NATURALARTIFICIAL

NATURAL ARTIFICIAL

The element undergoes spontaneous decay because it is unstable.

These reactions occur “spontaneously” (on its own)

We start with ONE element on theRIGHT side of the arrow and end up with TWO things on the product side (rightside)

For this change to happen, high‐energy particles are fired at the element.

In this reaction, two things are beingcombined:(1) The nucleus being bombarded(2) The high‐energy particle

We start with TWO things on the left side of the arrow and 2 or more things on the right side of the arrow

TRY THESENatural

Natural

Natural

Artificial

Natural

Artificial

Artificial

Balancing natural and artificial transmutation reactions

Remember the law of conservation of mass! We must have a balanced equation!

Balance the equation

4

2

He4

2

INDEPENDENT PRACTICE

• Complete the PRACTICE section• Please complete the classwork