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© Boardworks Ltd 20071 of 44. 2 of 44© Boardworks Ltd 2007.

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Presentation on theme: "© Boardworks Ltd 20071 of 44. 2 of 44© Boardworks Ltd 2007."— Presentation transcript:

1 © Boardworks Ltd of 44

2 2 of 44© Boardworks Ltd 2007

3 3 of 44 What is the periodic table? Mendeleev created the first modern periodic table. What does it show and why is it always in the same order?

4 © Boardworks Ltd of 44 What is an element?

5 © Boardworks Ltd of 44 Where were the elements made? There are 92 naturally-occurring elements and about 15 artificially-produced elements. Elements were originally made in stars. In the early stages of a stars life, light elements, such as hydrogen and helium, are formed. These fused together to make heavier elements such as carbon. Some of the even heavier elements were produced deep within stars and were sent out into the Universe when the stars exploded. Most of the artificially-produced elements have only been made in nuclear reactors or particle accelerators.

6 © Boardworks Ltd of 44 What are elements made of? Each element is made up of one type of atom, which is different to the atoms in any other element. Gold is an element made up of only gold atoms. Carbon is an element made up of only carbon atoms. Oxygen is an element made up of only oxygen atoms.

7 © Boardworks Ltd of 44 What are atoms made of?

8 © Boardworks Ltd of 44 What is the atomic number? Every element has a unique atomic number. This is the number of protons in the nucleus of each atom. What is the atomic number of this helium atom? A neutral atom must have equal numbers of protons and electrons, so the atomic number of an element also gives the number of electrons. Helium has 2 protons, so its atomic number is 2. Atoms are neutrally charged, so what links atomic number and the number of electrons? electron proton neutron

9 © Boardworks Ltd of 44 What are the properties of elements? A property is any characteristic feature of a substance. Properties of sodium include: The chemical properties of an element are determined by its atomic number. Are there any patterns in the properties of the elements? highly reactive solid but melts easily feels light (low density). Can you name any properties of the element sodium? A property is any characteristic feature of a substance.

10 © Boardworks Ltd of 44 Elements and atoms – true or false?

11 11 of 44© Boardworks Ltd 2007

12 12 of 44 How was the periodic table developed?

13 © Boardworks Ltd of 44 How are the elements arranged?

14 © Boardworks Ltd of 44 The periodic table Arranging all the elements by their atomic number and their properties led to the creation of… …the periodic table FrRaAcRfDbSgBhHsMtDsRg???????CsBaLaHfTaWReOsIrPtAuHgTlPbBiPoAtRnRbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXeKCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKrNaMgAlSiPSClArLiBeBCNOFNeHHe

15 © Boardworks Ltd of 44 Missing elements! In this periodic table the symbols are replaced by atomic numbers. Some of the numbers are missing – where? Two more rows of elements fit here. They are called the lanthanides and actinides.

16 © Boardworks Ltd of 44 The elements in the periodic table

17 © Boardworks Ltd of 44 Columns of elements What are columns of elements called? groups

18 © Boardworks Ltd of 44 Rows of elements periods What are rows of elements called?

19 © Boardworks Ltd of 44 Complete the sentences – periodic table

20 20 of 44© Boardworks Ltd 2007

21 21 of 44 Patterns: metals and non-metals on the right (except hydrogen) Where are these different types of elements grouped together in the periodic table? metals non-metals between metals and non-metals semi-metals on the left and centre Can you name a semi-metal element? Semi-metals have some properties similar to metals and other properties similar to non-metals.

22 © Boardworks Ltd of 44 Patterns: physical state Only two elements are liquids at room temperature. What are they? liquids Where are these elements of different states grouped together in the periodic table? in the middle and on the right solids on the far right (except hydrogen) gases on the left, in the centre and on the right bromine and mercury

23 © Boardworks Ltd of 44 Metals to non-metals, solids to gases

24 © Boardworks Ltd of 44 Patterns: reactivity of metals FrRaAcRfDbSgBhHsMtDsRg CsBaLaHfTaWReOsIrPtAuHgTlPbBiPo RbSrYZrNbMoTcRuRhPdAgCdInSn KCaScTiVCrMnFeCoNiCuZnGa NaMgAl LiBe What happens to the reactivity of metals down a group? Which is the most reactive metal? increase in reactivity What happens to the reactivity of metals along a period?

25 © Boardworks Ltd of 44 Which metal is more reactive?

26 © Boardworks Ltd of 44 Patterns: reactivity of non-metals increase in reactivity Group 0 elements are the most unreactive of all elements. For the remaining non- metals and semi-metals, reactivity increases up a group and along a period from left to right. Which is the most reactive non-metal/semi-metal? AtRn SbTeIXe GeAsSeBrKr SiPSClAr BCNOFNe He increase in reactivity unreactive

27 © Boardworks Ltd of 44 Which non-metal is more reactive?

28 28 of 44© Boardworks Ltd 2007

29 29 of 44 Patterns, atomic number and electrons What links atomic number and the properties of elements? The periodic table shows that patterns in the properties of elements are linked to atomic number. atomic number = number of protons atomic number = number of electrons number of protons = number of electrons Electrons! As atomic number increases by one, the number of electrons also increases by one. This means that the elements in the periodic table are also arranged in order of the number of electrons.

30 © Boardworks Ltd of 44 How are electrons arranged? Electrons are arranged in shells around an atoms nucleus. (The shells can also be called energy levels). This electron arrangement is written as 2,8,8. 1 st shell holds a maximum of 2 electrons 2 nd shell holds a maximum of 8 electrons 3 rd shell holds a maximum of 8 electrons Each shell has a maximum number of electrons that it can hold. Electrons will fill the shells nearest the nucleus first.

31 © Boardworks Ltd of 44 Electrons in period 1 Elements in period 1 only have electrons in the first shell. Why are there only two elements in period 1? The first shell can only hold a maximum of two electrons, so period 1 only includes the elements hydrogen and helium. What is special about the outer shell of helium? 12 HHe

32 © Boardworks Ltd of 44 Electrons in period 2 Elements in period 2 all have a complete first shell. The second shell is completed one electron at a time going across the period from left to right. What is special about the outer shell of neon? 2,12,22,3 2,4 2,5 2,6 2,7 2,8 LiBeBCNOFNe What happens to electrons in the second shell in period 2? 2

33 © Boardworks Ltd of 44 Electrons in period 3 2,8,12,8,22,8,3 2,8,4 2,8,5 2,8,6 2,8,7 2,8,8 Elements in period 3 have complete first and second shells. The third shell is completed one electron at a time going across the period from left to right. What happens to electrons in the third shell in period 3? NaMgAlSiPSClAr What is special about the outer shell of argon? 3

34 © Boardworks Ltd of 44 What are the patterns of electron arrangement? Consider the electron arrangements of the first 20 elements in the periodic table. What is the pattern of outer shell electrons in a group? 2,8,12,8,22,8,32,8,42,8,52,8,62,8,72,8, ,12,22,32,42,52,62,72, ,8,8,12,8,8,2 What is the pattern of outer shell electrons across a period? What is the pattern of full electron shells in a group?

35 © Boardworks Ltd of 44 Electron trends in the periodic table Trends down a group: The point at which a new period starts is the point at which electrons begin to fill a new shell. The number of a group is the same as the number of electrons in the outer shell of elements in that group, except for group 0. the number of outer shell electrons is the same; the number of complete electron shells increases by one. the number of outer shell electrons increases by one; Trends across a period: the number of complete electron shells stays the same.

36 © Boardworks Ltd of 44 Electrons and groups

37 © Boardworks Ltd of 44 Groups and periods

38 © Boardworks Ltd of 44 Whats the electron arrangement?

39 © Boardworks Ltd of 44 Names of groups in the periodic table

40 © Boardworks Ltd of 44 Periodic table and electron structure

41 41 of 44© Boardworks Ltd 2007

42 42 of 44 Glossary atomic number – The number of protons in an atom. Sometimes called the proton number. electron arrangement – A shorthand way of writing the number of electrons in an atoms electron shells. element – A substance made up of only one type of atom. group – A column in the periodic table containing elements with the same number of outer shell electrons and similar chemical properties. period – A row in the periodic table containing elements with the same number of full electron shells. periodic table – The table that lists all the elements in order of increasing atomic number, arranged into groups and periods. property – Any characteristic of an element.

43 © Boardworks Ltd of 44 Anagrams

44 © Boardworks Ltd of 44 Multiple-choice quiz


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