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How many different substances?. How many different substances can you think of?. There are millions of different substances! What are they all made of?. All substances are made of atoms. hydrogen and oxygen atoms. carbon and hydrogen atoms. iron, aluminium, silicon, oxygen and boron atoms.
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How many different substances? How many different substances can you think of? There are millions of different substances! What are they all made of?
All substances are made of atoms hydrogen and oxygen atoms carbon and hydrogen atoms iron, aluminium, silicon, oxygen and boron atoms carbon, nitrogen, hydrogen, oxygen and sulphur atoms All substances are made of very tiny particles called atoms. Many substances are made up of different types of atoms.
What is an element? copper carbon helium All substances are made of very tiny particles called atoms. There are about one hundred substances that are made up of justone type of atom. These are the elements. The elements are the simplest substances in the universe. The elements are the building blocks of all other substances.
Atoms in elements An element is a substance made up of only one type of atom. Copper is an element made up of copper atoms only. Carbon is an element made up of carbon atoms only. Helium is an element made up of helium atoms only.
Atoms and molecules of elements In some elements, the atoms are joined in groups of two or more. A particle containing atoms grouped in this way is called a molecule. Oxygen is an element made up of oxygen atoms only. How many atoms are there in an oxygen molecule? Other elements, that contain atoms joined in molecules are hydrogen, nitrogen, chlorine and bromine.
Symbols for elements A standard set of symbols is used to represent elements. The symbol for many common elements uses just the first letter of the name, for example H = hydrogen. Other elements have the first two letters, for example Li = lithium. However, some of the symbols are not always as you might expect, for example Pb = lead. Two important rules should be followed when writing the symbols of elements so that there is no confusion. • The first letter of an element’s symbol is always a capital letter, e.g. N (not n) for nitrogen. • If there are two letters in the element’s symbol, the second letter is always a small letter, e.g. Co (not CO) for cobalt.
Spelling with symbols Write down the symbols for each element listed and use these to spell out a word that matches the clue. • Board game: carbon,helium, two sulphurs • Relative: sulphur, oxygen, nitrogen • Fuel: carbon, oxygen, aluminium • Group of fish: sulphur, hydrogen, oxygen, aluminium • For the rubbish: boron, iodine, nitrogen. CHeSS SON COAl SHOAl BIN
Symbols for molecules of elements = = O2 = = H2 = = N2 In some elements, the atoms are joined together and form molecules. Combining the symbols of the atoms in a molecule gives you the formula for the molecule. What is the formula for the molecules in each element? oxygen hydrogen nitrogen There are groups of two atoms in each molecule.
Metals and non-metals in the periodic table Metals are on the left and in the centre. Non-metals are mostly on the right. The periodic table is a list of all the known elements that are arranged according to the similarities in their properties. What type of elements are between metals and non-metals?
Metal, non-metal or metalloid? Metals are on the left and in the centre of the periodic table. Non-metals are located mostly on the right. Metalloids sometimes behave like metals and sometimes like non-metals. Metalloids are located between metals and non-metals in the periodic table. Silicon is an example of a metalloid.
Combining elements How is it possible to have so many different materials from a limited number of elements?
Combining elements A small number of elements can be combined in many different ways to make a huge number of different compounds. To help understand this, just think about cheese! • How are so many different types of cheese produced? • What is the key ingredient in all cheeses? Milk is combined with a small number of ingredients under different conditions to make a huge number of different cheeses.
What is a compound? A compound is always made up of two or more different types of atom. A compound is the substance produced when two or more elements combine in a chemical reaction. Two elements, hydrogen (H) and oxygen (O), combine to make the compound, water. Which two elements combine to make the compound carbon dioxide?
Making a compound – carbon dioxide carbon (element) oxygen (element) carbon dioxide (compound) + A compound has very different properties to the elements from which it is made. A black solid that can be used as a fuel. A colourless gas that is essential for life. A colourless gas that is used to put out fires.
Making water hydrogen (element) oxygen (element) water (compound) + What are the elements that make up water? In what ways are the elements different to their compound? A colourless gas that is used in hot air balloons. A colourless gas that is essential for life. A liquid that is essential to our lives.
Chemical reaction to make water + hydrogen oxygen water In a chemical reaction new substances are formed. Elements combine with each other to make new substances called compounds. The substances that combine in a reaction are the reactants. The new substances produced in a reaction are the products. The products have different properties to the reactants from which they are formed. Compounds can also combine with elements or other compounds to make new compounds.
Atoms joining in a chemical reaction + hydrogen oxygen water + In a chemical reaction, the atoms in the reactants become joined in different ways and this is how new substances are formed. When the two elements, hydrogen and oxygen, combine in a chemical reaction, the hydrogen and oxygen atoms do not just mix together they become joined to one another.
Glossary atom – The smallest particle that can exist on its own. compound – Substance made up of two or more different elements that are chemically joined together. element – Substance made up of only one type of atom. formula – The symbols and numbers that represent the atoms in a substance. molecule – Two or more atoms that are chemically joined together. periodic table – Table in which all known elements are arranged based on their properties. symbol – One or two letters that represent an element.
