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Review of the Atom

About The Unit


Ngā Whāinga Ako


Copy this diagram into your book.


Overview

An atom is made up of two distinct parts. The nucleus and electrons.


The Nucleus


The Three Particles

The three particles have different electrical charges. Copy this table into your book and fill it out if you know the answers!

LocationElectric ChargeMass
Proton
Electron
Neutron

LocationElectric ChargeMass
ProtonNucleus+11
ElectronOrbits-10
NeutronNucleus01

Atomic Number

The number of protons inside the nucleus.

Mass Number

The number of protons + neutrons inside the nucleus.

NB: In a neutral atom, the number of protons is equal to the number of electrons. Why?


Practice

This is sodium. How many electrons does it have? How many protons does it have? What is its atomic number?


Practice

Draw this table in your book and fill it out to describe the following atom.

QuestionAnswer
Number of Protons
Number of Neutrons
Number of Electrons
Atomic Number
Mass Number


Isotopes

An isotope is when the element is the same but the number of neutrons has changed.