Nuclear Chemistry

Chapter 21

Nuclear Chemistry

Study of nuclear reactions and their uses in chemistry

nuclear reactions – change in matter originating in the nucleus of an atom

radioactive – nuclei spontaneously changing and emitting radiation

Nuclear Chemistry

Subatomic particles are involved proton and neutron nucleons

Can be determined by atomic number and mass number

Same atomic number, different mass number isotope

Radioactive nuclei radionuclide Atoms with radionuclides radioisotopes

Nuclear Chemistry

Radionuclides Unstable Emit particles and electromagnetic

radiation Radioactive decay

Radioactive Decay

1 – alpha radiation α Helium - 4 particles, aka alpha particles 4

2He

23892U 234

90Th + 42He

Alpha radiation - Sample

What product is formed when radium-226 undergoes alpha decay?

22688Ra 222

86Rn + 42He

What element undergoes alpha decay to form lead-208?

21284Po 208

82Pb + 42He

Radioactive decay

2 – beta radiation β High speed e- 0

-1e or 0-1 β

13153I 131

54Xe + 0-1e

Radioactive decay

3 – gamma radiation γ High energy photons 0

0γ Energy lost when nucleons reorganize

Radioactive decay

4 – positron emission Same mass as e-, opposite charge 0

1e

116C 11

5B + 01e

Positron can convert proton to neutron

Radioactive decay

5 – electron capture Capture of electron by nucleus from

electron cloud 0

-1e consumed, not formed

Electron Capture - Sample

Write nuclear equations for the following processes: a) Mercury-201 undergoes electron

capture b) Thorium-231 decays to form

protactinium-231 a) 201

80Hg + 0-1e 201

79Au

b) 23190Th 231

91Pa + 0-1e

Electron Capture-Sample 2

Write a balanced nuclear equation for the reaction in which oxygen-15 undergoes positron emission 15

8O 157N + 0

1e

Nuclear Transmutations

Nuclei changed by being struck by neutron or nucleus

Commonly represented by listing in order the target nucleus, the bombarding particles, the ejected particles, the product nucleus 14

7N (α,p)178O

147N + 4

2He 11p + 17

8O

Nuclear Transmutations-Sample

Write the balanced nuclear equation for the process summarized as 27

13Al (n, α) 24

11Na 27

13Al + 10n 4

2He + 2411Na

Using shorthand notation, write the nuclear reaction 16

8O + 11H 13

7N + 4

2He 16

8O (p, α) 42He