5 isotopes

Isotopes

Objectives:5.2 To identify the advantages & disadvantages of using isotopes in industry, medical science, basic research & in the environment

Are atoms of the same element, but have a different number of neutrons

ex. Carbon can have 6 or 8 neutrons

Isotopes:

C 12

6 C 14

6

6 neutrons 8 neutrons

Have the same number of protons & electrons

Have the same atomic number

Have the same chemical reactivity

Isotopes:

C 12

6 C 14

6

What statement is false?

A) Isotopes have the same number of protons

B) Isotopes have the same number of neutrons

C) Isotopes have the same number of electrons

Given the three hypothetical atoms below, which are isotopes of the same element?

A 10

6 B 10

5 C 12

6

Different # neutronsSame # protons

4 neutrons 5 neutrons 6 neutrons

6 protons 5 protons 6 protons

According to the graph below, how many isotopes of nitrogen (N) are there?

Atomic Number

Ato

mic

Mass

7 85 6

12

13

14

15

Different # neutronsDifferent Atomic MassSame Atomic Number

Find atomic number of N Trace up – each point represents an isotope

2 isotopes

According to the graph below, what is the atomic mass of each isotope of oxygen?

Number of Protons

Nu

mb

er

of

Neu

tron

s

9 107 8

7

8

9

10

Find the number of protonsTrace up – each point represents an isotope

3 isotopes

Trace along & find the number of neutrons for each isotope

Add the number of protons & neutrons together for each isotope

Atomic mass = 18

Atomic mass = 17

Atomic mass = 16

Occur naturally in nature & are made artificially

Most natural isotopes are stable

Some natural & artificial isotopes are unstable When unstable, release radiation

(radioisotopes)

Isotopes:

Unstable isotopes (radioisotopes) can be used for: Cancer therapy Medical diagnosis Nuclear power plants Irradiation of foods Research Environment

Radioisotopes:

Isotopes are atoms of the same element, but with a different number of neutrons

Same atomic number, number of protons & electrons and chemical reactivity

Natural isotopes tend to be stable

Artificial isotopes are not stable & can release radiation

Activities:

Physical Science Worksheet #9

References

Student Study Guide – Physical Science 416/436 - MEQ

Science Quest – Grenier, Daigle, Rheaume – 1998, Cheneliere

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