periodic table chemistry definition compound chemistry definition

#PERIODIC TABLE CHEMISTRY DEFINITION COMPOUND CHEMISTRY DEFINITION FULL VERSION#
#PERIODIC TABLE CHEMISTRY DEFINITION COMPOUND CHEMISTRY DEFINITION DOWNLOAD#

The packing in the solid sulfur isn't accurate either and is just to suggest that the particles are closely packed together. Individual sulfur atoms, for example, are bigger than oxygen atoms. Note: For ease of drawing, all the particles above are not to scale. It doesn't matter how the atoms are arranged, whether singly or in pairs or in large indefinite groups - if they are all the same size and colour, then the diagram is showing an element.Įxamples where the atoms are in small well-defined groups If everything present has the same atomic number, then it is an element. If all the atoms in a model or diagram are the same size and colour, then we assume that they are all the same - they have the same atomic number. (We have already said that.)Ī substance is an element if all the atoms present have the same atomic number. For example, if an atom has 8 protons it is an atom of oxygen, and every oxygen atom contains 8 protons.Įlements are substances which can't be split into anything simpler by chemical means. The really important thing is that the number of protons defines what the atom is. The Periodic Table is arranged in order of increasing atomic numbers. If you look at the Periodic Table above, the little numbers in each box are the atomic numbers of the elements. The number of protons in an atom is known as the atomic number or proton number. The electrons surround the nucleus at relatively large distances. The protons and neutrons are found packed together in the nucleus at the centre of the atom and make up most of the mass of the atom. And in any case, you can't split atoms by chemical means. At that point you would have an individual copper atom.Ītoms themselves are made up of even smaller particles (protons, neutrons and electrons), but if you split the copper atom into those, you wouldn't have copper any longer. If you had some copper and tried to chop it up into smaller and smaller pieces, eventually you would end up with the smallest possible bit of copper.

#PERIODIC TABLE CHEMISTRY DEFINITION COMPOUND CHEMISTRY DEFINITION FULL VERSION#

if something appears in a full version of the Periodic Table it is an element otherwise it isn't. This doesn't have all the most recently discovered elements, but it has more than you will ever need at this level.

#PERIODIC TABLE CHEMISTRY DEFINITION COMPOUND CHEMISTRY DEFINITION DOWNLOAD#

You will find a simple Periodic Table which you can download from this site. Note: You really need a full-sized paper copy of a Periodic Table which you can read easily. I have simplified it by leaving out elements that you aren't likely to come across at this level. The Periodic Table lists all the known elements in a particular order which we will talk about in a minute. Copper is an element.Įlements are substances which can't be split into anything simpler by chemical means. Again copper is a simpler substance than copper(II) oxide.īut there is nothing you can do chemically to turn copper into anything still simpler. If you pass hydrogen over hot copper(II) oxide, the hydrogen removes the oxygen, and leaves pinkish-brown copper, Cu. Copper(II) oxide is obviously a simpler substance than copper(II) nitrate.

If you heat some blue copper(II) nitrate crystals, Cu(NO 3) 2,3H 2O, you get a chemical change and it turns into black copper(II) oxide, CuO, giving off nitrogen dioxide, oxygen and steam in the process. Cu is the symbol for copper the others are fairly obvious. They are just there to illustrate the complexity of various substances. Don't worry about it if you haven't done any work on symbols yet. I am going to include some chemical formulae in what comes next.

It also takes a quick look at the Periodic Table - a really important tool in chemistry. This page explains the difference between an element and a compound, and how both of these differ from mixtures.

Periodic table chemistry definition compound chemistry definition