Isotopes

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Characteristics of Isotopes

they are atoms of the same element with the same number of protons and electrons, but different numbers of neutrons

(as shown below)

isotopes have the same proton number but different nucleon numbers

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most elements occur naturally as a mixture of isotopes

> for example, chlorine has 2 isotopes: chlorine-35 and chlorine-37

but, a few elements do not have isotopes

> for example, all atoms of beryllium have 5 neutrons and 4 protons

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Physical Properties of Isotopes

THEY HAVE:

the same number of protons and electrons:

chemical reactions involve only the electrons, not neutrons

therefore, isotopes have similar chemical properties (eg.: both chlorine-35 and chlorine-37 react with sodium to produce sodium chloride

different numbers of neutrons:

physical properties are affected by mass

isotopes have different masses and therefore, different physical properties (eg.: hydrogen-2 has a slightly higher boiling point and density than hydrogen-1)

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Uses of Isotopes