Welcome to our Beginner's Guide to the Periodic Table of Elements.
Are you struggling to get your head around the periodic table? It’s a common issue for students. The periodic table is complicated.
When you think about it, there are 118 elements, classified into various categories according to their properties, and each element has a symbol and key attributes. That’s a lot of information. To help you navigate the periodic table and learn about its history, we’ve produced this Beginner’s Guide to the Periodic Table to help High School students of all levels master the table of elements!
In this guide, we’re going to bring some clarity to the periodic table for students (and parents). But first, let’s look at what’s in this overview article:
The periodic table of the elements – or just the periodic table – is a table that displays all of the elements. As there are 118 known elements (at this point), it is important that they be organised in a convenient and sensible way. The periodic table is an attempt to do this by sorting elements into periods and groups according to the number of electron shells and their electronic configuration.
The term element refers to atoms that have a specific number of protons (a subatomic particle with a positive charge +) in their atomic nuclei. We use the number of protons in the nucleus to identify the element, and call this its atomic number (Z). For example, atoms with just one proton are hydrogen, atoms with two protons are helium, atoms with six protons are carbon, and so on.
Most substances we find on earth are composed of compounds, which are combinations of elements. A few elements are found in a pure form, like gold.
The discovery and naming of elements is now overseen by the International Union of Pure and Applied Chemistry (IUPAC). Research into new elements is an ongoing process.
The rows of the periodic table are called periods. Each element in a period has the name number of electron shells. (You can think of an electron shell as an orbit that an electron follows around the nucleus of the atom.)
The elements are arranged in order of increasing atomic number across a period from left to right, so each element has one more proton in its nucleus compared to the preceding one. The properties also change across a period – that’s why metals are on the left, and non-metals on the right.
As the name suggests, the periodic table is periodic – something recurs after a given interval. The periodic table is arranged to recognise that certain chemical and physical properties of the elements recur – this is called the Periodic Law. Once the end of a period is reached, the elements continue in the next period below, such that they end up underneath an element with similar properties.
This is why each column ends up containing elements that have similar properties – each column is called a group.
A group is a column of elements in the periodic table. Each group contains elements with similar physical or chemical characteristics, which mostly arise from the number of electrons in their outermost electron shell (called the valence shell).
There are 18 groups in the periodic table, corresponding to its 18 columns and they are numbered from left to right. Some of these groups have quite different properties from others, like the noble gases, but some share similar properties, like the transition metals, and are sometimes considered together.
This is how we have divided our Guide:
|Groups||Number of elements|
|1||Group 1 (Hydrogen and alkali metals)||7|
|2||Group 2 (Alkaline earth metals)||6|
|3||Groups 3-12 (Transition metals)||38|
|5||Group 17 (Halides)||6|
|6||Group 18 (Noble gases)||7|
The periodic table as we use it today was created by Dmitri Mendeleev in 1869. However, Mendeleev’s table was not the first attempt at bringing order to the elements.
As early as 1789, chemists like Antione Lavoisier attempted to group the known elements scientifically. Lavoisier grouped them as gases, metals, nonmetals, and earths. Later chemists attempted to find other laws to categorise them, but it wasn’t until Alexandre-Émile Béguyer de Chancourtois noticed the periodicity of the elements and arranged them based on atomic weight in 1862 that an early form of the periodic table was developed. De Chancourtois’ table was a helix or screw.
Subsequent chemists struggled to organise the elements satisfactorily until John Newlands observed similar properties occurring every 8th element. Newlands called this the Law of Octaves after observing similar patterns to those in music. This allowed him to predict the position of missing elements that had not been discovered yet. German chemist Julius Lothar Meyer further refined the arrangement of the elements in 1864 and grouped them according to their valence, a property that describes how elements form compounds or molecules. This arrangement underlies the groups that appear in the modern periodic table.
Mendeleev’s table also had gaps corresponding to the yet-to-be-discovered elements, and sometimes elements’ positions were switched to group them better.
Back in 1869 scientists did not know about protons, electrons and electron shells that result in the periodic table’s structure. They arranged the elements based on physical and chemical properties. It wasn’t until the 1950s that the underlying science was understood and the periodic table took on the form that’s familiar today.
To help you use this Guide, we’ve incorporated the following elements (pun intended!):
Use the chapter titles to navigate through the various groups of elements.
Each chapter of this guide has a contents table to help you navigate quickly to each element.
Use the information to reinforce your knowledge and if you’re at Strathfield campus, check out our Periodic Table Display.
The Matrix Strathfield Campus has a Periodic Table display with samples of all the common elements (sorry, we don’t have a particle accelerator to create exotic elements!). We’re pretty proud of it, so you should check it out if you’re on campus.
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