The origins on the periodic table begin with the work of John Newlands and Dimitri Mendeleev.
Atomic structure is the positively charged nucleus and the negatively charged electrons circling around it, within an atom.
Elements names and symbols are used to identify the different elements of the periodic table. In this section you will explore why elements are named the way they are and also the importance of symbols of these elements and how they are used in the periodic table.
Elements are all around us in the everyday world. In this section you will explore how the periodic table relates to our everyday life and how we use this information to relate the elements around us to our lives.
Groups and Periods are the columns and rows of the periodic table. In this section you will explore how the periodic table was put together and the two main arrangement of the periodic table focusing on the groups and periods and metals and non metals.
Metals and non metals make up all of the periodic table and they are arranged in a certain order.
Elements compounds and mixtures are all unique combinations of different atoms in different ways.
States of matter are the different forms we find elements, compounds and mixtures in the periodic table as solids liquids and gases.
Changes of state happen when solids, liquids and gases change between each other due to energy being added or taken away.
Physical properties of a substance are a way of measuring different features of that element or compound and classifying them.
Chemical properties of a substance are a way of measuring its reactivity an the way it interacts with other atoms to form compounds.
The atomic number of the elements provides information on the number of protons in the nucleus.
Atomic mass refers to the mass of both the protons and neutrons and is always the larger of the two represented in the periodic table.
Isotopes are elements with different numbers of neutrons in the nucleus but the same number of protons.
Ions are atoms or groups of atoms that have either lost or gained electrons so they have a positive or negative charge.
Gaps in the periodic table were first used by Dimtri Mendeleev when he could not find an element to fit the patterns of the groups and periods he was using. Mendeleev knew there would be undiscovered elements so used these gaps to prompt other scientists to start looking for them.
The abundance of elements in the universe and on earth is a measure of how much in terms of mass or percentage of that element is naturally occurring. Some elements in the universe such as hydrogen and helium, very basic elements make up large amounts of matter in the universe. Where as rare elements like francium and caesium are much less abundant and rare.
Some elements have to be made in the lab as they cannot exist in the natural world like most elements. These elements sometimes require special conditions and equipment to force them to decay or force two different nuclei together.
Alchemy is a term used to describe the historical study of elements and matter with the goal of creating an elixir for immortality or trying to change metals into more precious metals.
Alchemy whilst being the study of such wild theories as the transmutation of metals and prolonging of life also had many useful origins of chemistry today from drug design to experimental techniques we still use in the lab today.
Alchemy symbols are illustrations that have been used by alchemists for hundreds of years to communicate between alchemists about different elements and scientific methods in the pursuit of alchemy. It was also used as a way to protect their discoveries and findings as often they were only known by a few people.
The first recorded use of symbols to refer to elements was by Ancient Greek philosophers who used their studies of the planets and the days to correspond to their understanding of the elements.
Thee Three Primes was a series of three known elements that alchemists believed determined diseases, life and the soul in a humans life and control of these elements could heal illness and create life.
Alchemy symbols have not just been used for elements across the ages but also to represent compounds and experimental techniques in chemistry.
Metallurgy is the study of metals and related physical and chemical properties. Much like alchemy it has been around for thousands of years but is still relevant in modern times due to its use in manufacturing and technology.
Atoms make up all matter around us, they are the smallest part of all things. Atoms in the periodic table all have different numbers of protons and are known as elements and they can be combined to make compounds and molecules
Bonding describes how metallic and non metallic elements of the periodic table exist as elements or combined together to form new compounds with different properties.
Metallic bonding is the bonding found in metals, positive metal ions surrounded by a sea of delocalized electrons.
Covalent bonding is the bonding found in non metals, involving the sharing of a pair of electrons or more between the atoms.
Intermolecular forces are the weak attractions between molecules that are covalently bonded.
Giant covalent structures exist when many atoms are covalently bonded in a large structure.
Ionic bonding is the bonding formed when metals and non metals transfer electrons creating oppositely charged ions.
Ionic compounds have a number of properties due to their bonding, they are brittle, non conductive as a solid and have high melting and boiling points.
Groups in the periodic table are the columns where elements with similar properties are found grouped together.
The periods of the periodic table are the rows that run from left to right in the periodic table. The elements are not arranged in these because of similar properties but because of their increasing atomic number from left to right.
States of Matter are the different forms that elements, compounds and mixtures will exist in as either solids, liquids or gases depending on how close their particles are.
Whilst the general trend that metals are solids and non-metal are gases, liquids and solids hold true and as you progress down the non-metals there are more solids there are some key exceptions.
All elements have differing physical properties. Some of these physical properties are appearance, melting point, boiling point, density, solubility and texture.
The density of elements in the periodic table is a measure of the number of atoms and their mass when they occupy a certain volume of space.
All elements in the periodic table have chemical properties. Chemical properties are how they react with other elements to form compounds and new substances.
Reactivity is a measure of how easily an element will combine with other elements to form compounds. Some elements are unreactive and need energy putting in others will react spontaneously and easily.
Atomic radius is the measure of the distance from the centre of the nucleus to the outer electron.
The nuclear charge of an atom is the measure of the effect of attraction between the protons in the nucleus and the outer electron
Shielding is the effect of the inner shells of electrons on weakening the attraction between the protons in the nucleus and the outer electron.
Ionisation energy is a measure of the amount of energy required to remove an outer electron from an atom creating a positively charged ion.
Oxidation states are a measure of the difference in the number of protons and electrons in an ion or atom
Radioactivity is a property of a number of elements in the periodic table where their nuclei break down and release particles such as alpha, beta and gamma particles.
All elements in the periodic table have a place based on their atomic number and they are sorted into different groups and periods based on their reactivity and physical properties.
Group 1 is the first group in the periodic table containing elements that are commonly known as the Alkali metals. They are all metals and increase in reactivity down the group and when reacted with water form alkali solutions
The Group 2 Alkaline earth metals are the 2nd group in the periodic table and are just before the transition metals. They are all similar in their color of silvery/white metals and react with water to form alkaline solutions. They are however not as reactive as the group 1 metals as they have 2 valence electrons instead of 1.
The transition metals is a term given to the group of metals that occupy the centre of the periodic table. They are known as the transition elements as they bridge the gap between group 2 and 3. They are all metals, form coloured compounds and can act as catalysts with variable oxidation states.
The Halogens in Group 17 are non metal elements that are diatomic and simple covalently bonded. They decrease in reactivity down the group but increase in their melting and boiling points.
Group 18 the Noble Gases are the name given to a collection of gases that exist in Group 18 at the very end of the periodic table. They are all non metals and exist as monoatomic gases which are relatively inert and unreactive due to their full outer shell of electrons.
The Metalloids is the term given to the elements in the periodic table that exist between metals and non metals on the right hand side. These are elements that exhibit both properties of metals and non metals.
The lanthanides are a series of chemicals in the expanded periodic table that have an expanded number of orbitals beyond that of the transition metals. The lanthanides are mostly soft metals with their hardness increasing across the period. Whilst they are metals and can conduct electricity the lanthanides have a relatively high resistivity.
Electrons are essential components of an element and decide its reactivity and bonding. They have their own unique properties known as quantum numbers which makes them all unique, existing in a number of sub orbitals around a nucleus.
Our understanding of the atom and nucleus and electrons that surrounds it has come a long way since Ancient Greek times to our understanding of today. With this understanding there have been big leaps in technology and theories that have disproved other theories leading to the model we have today.
The modern Atomic Model was first developed by two key scientists Lavoisier and Dalton with the help of others. They formulated the key concepts of the law of conservation of mass and the existence of atoms as the building blocks of all matter using their knowledge of chemical reactions.
J.J Thomson contributed massively to the model of the atom and the modern day theory. His work involved the use of cathode ray tubes and identifying a particle lighter than the atom itself, the electron.
The work of J.J Thomson’s student, Ernest Rutherford, led to the discovery of the Proton. Working with alpha particles fired at a piece of gold foil it was observed that instead of passing straight through it was scattered. Suggesting there was something large in the centre of the atom.
By the 1930’s the atom consisted of a proton as a positive area of charge and electrons orbiting it but there was still a piece missing. It was not until 1932 that James Chadwick discovered a particle with the same mass of a proton but no overall charge, the neutron.
Wave Particle Duality was a revolutionary way of treating electrons as not just particles but also as waves at the same time. This opened up new doors in the explanation of the atom and its behaviours influencing the field of Quantum Mechanics.
Now that the electron could be treated as a wave and as a particle, the work of Werner Heisenberg was important in quantifying this as a mathematical concept and furthering our understanding of the mysterious electron.
Erwin Schrodinger as well as being famous for his cats in radioactive boxes was a driving force behind the treatment of electrons as both waves and particles and the treatment of electrons using quantum mechanics, a field of science that delved deeper into the mathematics and theory of sub atomic particles.
The physical properties of elements describes how the elements interact with the environment around them, especially temperatures and when they are placed into different substances.
Solubility is a physical property that determines whether an element or compound will dissolve in a solvent to form a solution
Crystal structure is a concept used to describe the three dimensional arrangement of atoms in a solid.
Lattice arrangements are representations of atoms in a three dimensional structure very often repeated over and over again with exactly the same symmetry.
Chemical properties is a term used to describe the behavior of elements when they react with each other and how they interact form compounds.
The atomic radius is a measure of the distance from the nucleus to the valence electron.
Nuclear charge is a measure of the effect of the number of protons in the nucleus and their ability to attract the negative electrons in orbits around the nucleus.
Shielding is the measure o the effect of inner sub shells of the S P D and F on their interference of the nuclear charge of the protons on the valence electron.
Ionic radius can be defined as the size of the radius of an ion from the nucleus to the valence electron. The ionic radius is difficult to measure due to the overlap of ions in a lattice structure.
Electron affinity is a measure of the energy released when an electron is added to an atom to create a negatively charged ion.
Electronegativity is a measure of the ability of an atom to attract electrons towards it in a covalent bond
Bond strength is the measure of how strong a bond is in terms of the energy needed to make and break the bond
Intermolecular forces are the forces of attraction that exist between covalent compounds holding them together. There are three different types of different strengths.
London dispersion forces are the weakest type of intermolecular forces and require very little energy to overcome them. They are very often found in non polar molecules that are in simple covalent compounds or elements.
Dipole - Dipole forces are usually found between molecules that have a difference in electronegativity so the electrons are unevenly distributed meaning that the molecule is polar. Due to its polarity this means a weak dipole forms which forms a weak intermolecular attraction to the molecule next to it.
Hydrogen bonding is the strongest type of intermolecular force that exists between simple covalent compounds and molecules. It exists when the two elements in a covalent bond have a large electronegativity difference such as when hydrogen is bonded to either fluorine, oxygen or nitrogen.
Transition metals are found in the centre of the periodic table between group 2 and 3. As part of the extended periodic table it makes up 10 groups from 2 to 3 and each of the metals has metallic bonding and a unique set of properties due to the d shell sub orbital of electrons.
Complex ions form when a metal ion is surrounded by ligands that coordinately bond to the metal ion forming a complex.