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ScienceOnline is an interactive resource for students and teachers of science.

The site provides access to a range of activities related to the New Zealand science curriculum for Years 9-11. Both Astronomy and Earth Science have been included as well as the core science areas of Physics, Chemistry and Biology. There are interactive notes and diagrams, self-marking tests, and useful links to other science websites. The site is completely up to date with NCEA requirements at Year 11 with details of achievement standards linked to topics in each of the five subject areas.

ScienceOnline has been developed by Peter Biggs, former science teacher and author of the Blue Science Book, and Sandy McGivern, science teacher, who manages the site.

In this document:

• Introduction
• Symbols for the elements
• The Periodic Table
• The physical states of the elements
• Mnemonic rhyme for learning the first twenty elements

Introduction

An element is a substance that cannot be broken down into any further different substances. It consists of just one type of atom - that is, atoms with the same atomic number.

This means that all the atoms of a pure element have the same number of protons.

Symbols for the elements

Each element has a shorthand symbol called its chemical symbol. This is written as one or two letters - the first letter is always a capital letter and the second (if there is one) is a small letter.

Examples are hydrogen H, chlorine Cl, sodium Na, copper Cu.

There are about 100 known elements but this year you will only need to know the chemical symbols of the first 20 elements and some other more common elements.

The Periodic Table

The elements can be written in order of their atomic numberand arranged into columns (called groups) of elements with similar chemical properties.

This listing is called the Periodic Table and was first discovered by the Russian chemist Mendeleyev in 1869.

The Periodic Table also divides into metals and non-metals. Hydrogen is unique - it can behave as a metal or a non-metal.

The importance of the Periodic Table is that it groups the elements according to their chemical properties. The pattern in this grouping is more easily understood and learned.

The physical states of the elements

The elements are composed of atoms or molecules (groups of atoms). They will also be found as a solid _(s), liquid _(l) or gas _(g) at room temperature.

• Metals: These are all atoms and are solid except for mercury Hg (a liquid).
  

Examples: Na, Ca, Cu

• Non-metals: These exist as molecules except for the Inert Gases (Group 18) which exist only as atoms.
  
  

Examples:

Mnemonic rhyme for learning the first twenty elements

The bold letters of the following rhyme correspond to the chemical symbols for the first 20 elements. If you don't like this one, try making one up your own one!

Henry He Likes Beer Bottles Cold Not Over Frosty. Nelly's Nanny Might Although, Silly Person She Climbs Around Kinky Caves!