nuclear chemistry. radioactivityradioactivity the spontaneous decomposition of a nucleus to form a...

Nuclear

Chemistry

Nuclear

Chemistry

RadioactivityRadioactivityRadioactivityRadioactivity

The spontaneous decomposition of a nucleus to form a different nucleus accompanied by a release of energy or a particle

ORThe spontaneous transformation of an

unstable atomic nucleus into a stable product while emitting radiation

The NucleusThe NucleusThe NucleusThe Nucleus

The atomic nucleus is made up of protons and neutrons which are collectively called nucleons.

Nuclide – in nuclear chemistry the atom is referred to as the nuclide.

NuclidesNuclidesNuclidesNuclides

Nuclides are represented by two ways:

Radium-228(name of element followed by mass number, which is the # of

protons + neutrons)

228 (mass number)

Ra (symbol)

88 (atomic number which is the # of protons as well as the # of electrons)

1)

2)

141466C the mass number C the mass number

is…is…

141466C the mass number C the mass number

is…is…1. 14

2. 6

Answer: 14

141466C the atomic number C the atomic number

is…is…

141466C the atomic number C the atomic number

is…is…1. 14

2. 6

Answer: 6

141466C has _____ protonsC has _____ protons141466C has _____ protonsC has _____ protons

1. 6

2. 14

3. 8

Answer: 6

141466C has _______ C has _______

neutrons…neutrons…

141466C has _______ C has _______

neutrons…neutrons…1. 6

2. 14

3. 8

Answer: 8

2092098484Po has _ neutrons and _ Po has _ neutrons and _

protonsprotons

2092098484Po has _ neutrons and _ Po has _ neutrons and _

protonsprotons1. 209 N, 84 P

2. 84 N, 209 P

3. 125 N, 84 P

4. 84 N, 125 P

Answer: 125 N, 84 P

Cobalt – 60 has __neutrons and __ Cobalt – 60 has __neutrons and __ protons protons

Cobalt – 60 has __neutrons and __ Cobalt – 60 has __neutrons and __ protons protons

1. 27 P, 33 N

2. 27 P, 60 N

3. 60 P, 27N

4. 60 P, 33N

5. 60 P, 60 N

Answer: 27 P, 33 N

Nuclear ReactionsNuclear ReactionsNuclear ReactionsNuclear Reactions

Chemical reactions involve the breaking and forming of bonds between different atoms.

In a nuclear reaction the situation is different – in a nuclear reaction changes occur involving the number of protons, neutrons, or electrons in a single atom.

Nuclear ReactionsNuclear ReactionsNuclear ReactionsNuclear Reactions

Proton is symbolized: 11

p

Electron is symbolized: 0-1

e 0-1

β

Neutron is symbolized: 10

n

Nuclear EquationsNuclear EquationsNuclear EquationsNuclear Equations

In nuclear equations the total of the atomic number and the total of the mass number must be equal on both sides of the equation.

Example:9 4 12 1 Be + He C + n4 2 6 0

Mass Number: 9+4 = 13 12+1 = 13

Atomic Number: 4+2 = 6 6+0 = 6

This is also called a transmutation reaction, because the beryllium-9 became carbon-12.

Practice: Complete the following nuclear Practice: Complete the following nuclear equations:equations:

Practice: Complete the following nuclear Practice: Complete the following nuclear equations:equations:

1. 218 214 Po + Pb 84 _________ 82

2. 253 4 256 Es + He Md + 99 2 101 ________

3. 142 142 Pm + Nd 61 _________ 60

RadiationRadiationRadiationRadiation

Radiation comes from the nucleus of an atom. Unstable nucleus emits a particle or energy

alpha

beta

gamma

He42

A. Types of RadiationA. Types of RadiationA. Types of RadiationA. Types of Radiation

Alpha particle () helium nucleus paper2+

Beta particle (-) electron e0

-11-

Gamma () high-energy photon 0

concrete

lead

Metal Foil

He42

A. Types of RadiationA. Types of RadiationA. Types of RadiationA. Types of Radiation

Alpha particle () helium nucleus paper2+

Alpha Emission – an alpha particle () is 2 protons and 2 neutrons (or a helium atom) bound together and is emitted from the nucleus during some kinds of radioactive decay.

210 206 4 Po Pb + He

84 82 2Paper or clothes will shield you from alpha particles.

B. Types of RadiationB. Types of RadiationB. Types of RadiationB. Types of Radiation

Beta particle (-) electron

e0-1 1-

Metal Foil

Beta Emission – a beta particle () is an electron emitted from the nucleus when a neutron is converted to a proton.

1 1 0 n p + 0 1 -1

14 14 0 C N + 6 7 -1

Metal foil will shield you from beta particles.

D. Types of RadiationD. Types of RadiationD. Types of RadiationD. Types of Radiation

Gamma () high-energy photon 0

concrete

lead

Gamma Emission – gamma rays () are high-energy electromagnetic waves emitted from a nucleus as it changes from an excited state to a ground energy state. Very similar to light, but is much more dangerous. Gamma emission usually occurs immediately following other types of decay.

Lead or concrete will protect you from gamma rays.

Practice: Identify and complete the following Practice: Identify and complete the following nuclear reactions:nuclear reactions:

Practice: Identify and complete the following Practice: Identify and complete the following nuclear reactions:nuclear reactions:

1. 9 4

Be + He

__________ 4 2

2. 234 234

Th Pa +

90 91 ___________

Practice: Identify and complete the following Practice: Identify and complete the following nuclear reactions:nuclear reactions:

Practice: Identify and complete the following Practice: Identify and complete the following nuclear reactions:nuclear reactions:

3. Write an equation to represent the decay of thorium-230 by alpha emission.

RadiationRadiationRadiationRadiation

Effects of Radiation - The effects of radiation depends on the amount and exposure. Massive doses can be deadly.

DNA molecules are sensitive to alpha, beta, positron, gamma, and x-rays.