<h2>How small is the nucleus?</h2>
<p>The nucleus of an atom is very small. We can compare an atom with a soccer stadium. If the whole atom is as big as a soccer stadium, the nucleus is only the size of a pea in the middle of the stadium! This should help you see that the atom is mainly made up of empty space. If you removed all the empty space from the atoms in your body, you would become the size of a grain of salt!</p>
<p><img alt="" src="https://data.ulearngo.com/assets/b7581716-5861-4286-b1bd-5a3fad1b98bf"/></p>
<h2>Relative Atomic Mass</h2>
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<h3>Definition: Relative Atomic Mass</h3>
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<p>The relative <a data-lesson="atomic-mass" data-subject="chemistry" data-tutorial="atoms-molecules-ions" href="https://app.ulearngo.com/chemistry/atoms-molecules-ions/atomic-mass">atomic mass</a> of an element is the average mass of all the naturally occurring <a data-lesson="isotopes" data-subject="chemistry" data-tutorial="chemistry-essential-ideas" href="https://app.ulearngo.com/chemistry/chemistry-essential-ideas/isotopes">isotopes</a> of that element. The <a data-lesson="ideal-gas-laws" data-subject="chemistry" data-tutorial="states-of-matter" href="https://app.ulearngo.com/chemistry/states-of-matter/ideal-gas-laws">units</a> for relative atomic mass are atomic mass units.</p>
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<p>The relative atomic mass of an element is the <a data-lesson="atomic-and-atomic-mass-number" data-subject="chemistry" data-tutorial="chemistry-essential-ideas" href="https://app.ulearngo.com/chemistry/chemistry-essential-ideas/atomic-and-atomic-mass-number">number</a> you will find on the <a data-lesson="arrangement-of-the-elements" data-subject="chemistry" data-tutorial="classification-of-matter" href="https://app.ulearngo.com/chemistry/classification-of-matter/arrangement-of-the-elements">periodic</a> table.</p>
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Size of Nucleus

Chemistry generally explores the substances of which matter is composed, the investigation of their properties and reactions, and the use of such reactions to form new substances. 

Chemistry

Explore the essential ideas in chemistry, including the scientific method, laboratory skills and safety, states of matter, measurement uncertainty, models of the atom, electronic configurations, and more.


Essential Ideas in Chemistry

Atomic Mass And Diameter

Atoms And Compounds

Chemistry Essential Ideas Summary

Chemistry in Context

Discussion On Atomic Models

Electronic Configuration

Isotopes

Mathematical Treatment of Measurement Results

Measurement Uncertainty; Accuracy and Precision

Measurements

Models Of The Atom

Phases and Classification of Matter

Physical and Chemical Properties

Skills in the Laboratory

Structure of the Atom

Size of Nucleus

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