Atomic Symbols and Isotopes

mass # neutrons + protons

protons

# protons = # of electrons for a NEUTRAL atom

K3919

How many neutrons are present?How many electrons are present?

39 - 19 = 20 n0

19 e-

atomic # element Symbol

Name Symbol Protons Neutrons

Atomic Number

Mass Numbe

r

Carbon-14 6 8 6 14

Potassium-41 19 22 19 41

Lead-206 82 124 82 206

146C

Complete the Table Below

4119K20682Pb

What is radioactivity?

Radioactivity occurs when an unstable nucleus spontaneously emits fragments of the nucleus and/or energy.

Unstable Nucleus = Radioactive

Why are only some isotopes radioactive?

The ratio of protons to neutrons in the nucleus determines whether or not a nucleus is radioactive.

Radioactivity

Depicting Nuclear Reaction

For nuclear reactions, the sum of the mass numbers (top numbers) and the sum of the atomic numbers (bottom number)

must be the same on both sides.

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

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

Finding the Missing Nucleus

Mass Numbers234 = 4 + ?

? = 230

Atomic Numbers90 = 2 + ?

? = 88

?42

23490 HeTh

Ra23088

Finding the Missing Nucleus

Mass Numbers14 = 0 + A

A = 14

Atomic Numbers6 = -1 + Z

Z = 7

XeC AZ

01

146

N147

Examples of Transmutation Reactions

These are all transmutation reactions because the elements on the left side are

changed to produce a different element on the right side.

RaHeTh 23088

42

23490 NeC 14

701

146

HeBBeH 42

85

94

113

Emissions from Radioisotopes

Type of Particle Emitte

d

Description Symbol Mass Charge

Why is it Emitted

?

AlphaA HeliumNucleus 4 amu +2

Nucleus is too large.

BetaA Fast Moving

Electron -1Too many neutrons

GammaElectromagneti

c Radiation 0 amu 0Too much

energy

4242 orHe

0101 ore

00

amu1840

1

A radioisotope is a nucleus that is radioactive or unstable.

Writing Nuclear Decay Equations

Write the nuclear decay equation for the alpha decay of uranium-238.

ThHeU 23490

42

23892

Start your decay equation by writing the symbol for this nucleus and then follow it

with an arrow.

Write the symbol for the type of decay.

Mass Number: 238 = 4 + ? ? = 234

Atomic Number: 92 = 2 + ? ? = 90

Write the nuclear decay equation for the beta decay of iodine-131.

Mass Number: 131 = 0 + ? ? = 131

Atomic Number: 53 = -1 + ? ? = 54

Writing Nuclear Decay Equations

XeeI 13154

01

13153

Start your decay equation by writing the symbol for this nucleus and then follow it

with an arrow.

Write the symbol for the type of decay.

CC 146

00

146

Write the nuclear decay equation the emission of a gamma ray from carbon-14.

Mass Number: 14 = 0 + ? ? = 14

Atomic Number: 6 = 0 + ? ? = 6

Writing Nuclear Decay Equations

Start your decay equation by writing the symbol for this nucleus and then follow it

with an arrow.

Write the symbol for the type of decay.

Examples of Transmutation Reactions

These are all transmutation reactions because the elements on the left side are

changed to produce a different element on the right side.

RaHeTh 23088

42

23490 NeC 14

701

146

HeBBeH 42

85

94

113

Decay Series for Uranium-238

This diagram shows the

steps that an isotope of

uranium takes to reach a

stable isotope, lead-206.

A Closer Look at the Decay Series

Write a nuclear decay equation for what we occur to uranium-234 according to this decay series.

HeThU 42

23090

23492

A Closer Look at the Decay Series

Write a nuclear decay equation for what we occur to lead-210 according to this decay series.

210 210 082 83 1Pb Bi e

Writing Nuclear Decay Equations

Write the nuclear decay equation for the alpha decay of uranium-238.

ThHeU 23490

42

23892

Start your decay equation by writing the symbol for this nucleus and then follow it

with an arrow.

Write the symbol for the type of decay.

Mass Number: 238 = 4 + ? ? = 234

Atomic Number: 92 = 2 + ? ? = 90

Write the nuclear decay equation for the beta decay of iodine-131.

Mass Number: 131 = 0 + ? ? = 131

Atomic Number: 53 = -1 + ? ? = 54

Writing Nuclear Decay Equations

XeeI 13154

01

13153

Start your decay equation by writing the symbol for this nucleus and then follow it

with an arrow.

Write the symbol for the type of decay.

CC 146

00

146

Write the nuclear decay equation the emission of a gamma ray from carbon-14.

Mass Number: 14 = 0 + ? ? = 14

Atomic Number: 6 = 0 + ? ? = 6

Writing Nuclear Decay Equations

Start your decay equation by writing the symbol for this nucleus and then follow it

with an arrow.

Write the symbol for the type of decay.

Protecting Ourselves from Radioactive Particles

Positive Uses of Nuclear Chemistry

Nuclear Power Nuclear Medicine

Kills Bacteria on Food