1. Properties of an Atom In this presentation you will:
Most reactive
Least reactive
Potassium K Sodium Na Calcium Ca Magnesium Mg Aluminum Al Carbon C Zinc Zn Iron Fe Tin Sn Lead Pb Hydrogen H Copper Cu Silver Ag Gold Au Platinum Pt Cl Na + -
In this presentation you will:
explore the reactivity of different atoms
explore the reactivity series
explore the bonding of atoms
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2. Introduction
In this presentation, you will explore the differing reactivities of elements and look at the trends in reactivity in the halogens and the alkali metals.
You will explore the reactivity series and its uses in predicting chemical reactions.
A + B C + D
You will also explore the different types of bonding that take place between atoms.
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3. Reactivity
All elements have different properties. Some elements are similar; others display completely different properties.
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4. Reactivity
Group
Period
The periodic table displays the elements, so that they can be categorized into groups and periods that have similar properties.
The different properties of different elements lead to each one having a different reactivity.
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5. Reactivity
Reactivity is the ability of a substance to react with another chemical substance to produce new products.
Carbon (C) atom
Nucleus
Outer
electrons
Energy
levels
Inner
electrons
Elements have varying reactivities, which are related to the electron arrangements within their atoms.
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6. Neon (Ne) Atom (Noble Gas)
Reactivity
Atoms that have full electron outer energy levels are very unreactive. These electron arrangements are said to be stable.
Neon (Ne) Atom (Noble Gas)
Full outer
energy level
Elements with full outer energy levels appear in group 18 of the periodic table; they are called the noble gases.
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7. Question 1
“The reactivity of elements is related to the electron arrangement within their atoms.”
Is this statement true or false? +
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8. Question 1
“The reactivity of elements is related to the electron arrangement within their atoms.”
Is this statement true or false? +
True
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9. Electron Arrangement
For any element in the main block of the periodic table, it is easy to work out the electron arrangement within its atoms.
Period
The number of energy levels is the same as the period in which the element has been placed.
Sodium (Na) atom
Three energy levels
For example, sodium in period 3, has three energy levels.
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10. Electron Arrangement
Group
The number of electrons in the outer energy level is normally the same for each group member.
For example, all group 1 metals have one electron in the outer energy level.
Sodium (Na) atom
One electron in outer energy level
Group 18 elements have eight electrons in their outer shell (except helium, which has only two).
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11. Reactivity
Very reactive elements have atoms containing nearly empty or nearly full outer energy levels.
Nearly empty energy level
Nearly full energy level
For example, group 1 (alkali metals) and group 17 (halogens) contain very reactive elements.
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12. Reactivity
In both the alkali metals and halogens, each individual element has a different reactivity.
Increasing Radius
Reactivity varies up and down the groups.
This is due to outer electrons becoming further away from the nucleus as the atomic radius increases down each group.
Atomic radius
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13. Alkali Metals
The alkali metals are a family of very reactive metals. They include sodium (Na), potassium (K), and lithium (Li).
Potassium (K) atom
one outer electron
Their atoms have one electron in the outer energy level. When they react they lose that electron.
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14. Alkali Metals
These metals have to be stored in oil to exclude air and water because they will react immediately with both.
Potassium (K) atom
one outer electron
The reaction with water produces hydrogen gas and an alkali solution.
alkali metal + water metal hydroxide + hydrogen
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15. Question 2
Elements in group 1 of the periodic table, the alkali metals, have ...
A) one energy level
B) one electron in the outer energy level
C) a full outer energy level
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16. Question 2
Elements in group 1 of the periodic table, the alkali metals, have ...
A) one energy level
B) one electron in the outer energy level
C) a full outer energy level
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17. Alkali Metals
Lithium
Sodium
Potassium
When heated up in air, the alkali metals burn to form white solid oxides. The color given by the flame is characteristic of the metal.
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18. Alkali Metals
Potassium reacts more violently than sodium and lithium with both water and oxygen. It is more reactive.
Least reactive
This is because, as we go down the group, the outer electrons become further away from the nucleus and so become easier to take away.
Most reactive
Therefore, as you go down the group, the reactivity increases.
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19. Halogens
Fluorine gas, F2
Chlorine gas, Cl2
Bromine liquid, Br2
The elements in group 17 of the periodic table are known as the halogens. Halogens are a family of non-metals including fluorine (F), chlorine (Cl), and bromine (Br).
The halogens share many chemical and physical similarities. For example, all halogen molecules are diatomic (each one contains two atoms), so their molecular formulas are written as F2, Cl2, Br2, and so on.
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20. Halogens Cl
The halogens have similar properties because they all have one electron missing from an otherwise full outer energy level.
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21. Halogens
Each halogen has a slightly different reactivity. When halogens react, they gain an electron.
Most reactive
The closer the outer energy level is to the nucleus, the greater the attraction will be on the gained electron.
This means that the most reactive member of group 17 is fluorine, as the outer energy level is closest to the nucleus.
Least reactive
Reactivity decreases down the group.
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22. Question 3 Which one of these halogens is the LEAST reactive?
A) Iodine
B) Chlorine
C) Bromine
D) Astatine
E) Fluorine
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23. Question 3 Which one of these halogens is the LEAST reactive?
A) Iodine
B) Chlorine
C) Bromine
D) Astatine
E) Fluorine
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24. The Metal Reactivity Series
Scientists have organized the metals in order of reactivity by comparing them in certain reactions, such as:
Most reactive
Least reactive
Potassium K Sodium Na Calcium Ca Magnesium Mg Aluminum Al Carbon C Zinc Zn Iron Fe Tin Sn Lead Pb Hydrogen H Copper Cu Silver Ag Gold Au Platinum Pt
displacement reactions
reactions with acids and bases
reactions with water
reactions with oxygen
The assembled order is known as the metal reactivity series.
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25. The Metal Reactivity Series
The higher the metal in the series, the more reactive it is. This means that it will react faster and more vigorously than the metals below it. It can also displace the metals below it.
Most reactive
Least reactive
Potassium K Sodium Na Calcium Ca Magnesium Mg Aluminum Al Carbon C Zinc Zn Iron Fe Tin Sn Lead Pb Hydrogen H Copper Cu Silver Ag Gold Au Platinum Pt
The metal reactivity series has been assembled by examining the relative reactivities of all metals in the periodic table and comparing them with carbon and hydrogen.
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26. The Metal Reactivity Series
Carbon and hydrogen are also included in the series as reference points.
Most reactive
Least reactive
Potassium K Sodium Na Calcium Ca Magnesium Mg Aluminum Al Carbon C Zinc Zn Iron Fe Tin Sn Lead Pb Hydrogen H Copper Cu Silver Ag Gold Au Platinum Pt
The metal reactivity series can be used:
to predict whether a chemical reaction will take place
to predict the relative speed of a chemical reaction
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27. Reactivity Series The reactivity of a metal determines its uses.
Sodium
It explains why cutlery is not made from sodium; sodium reacts violently with water and tarnishes immediately once in contact with air.
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28. Reactivity Series
Gold is used for jewelry because it is not very reactive. It does not react readily with oxygen.
Gold
Gold is a shiny metal that retains its shininess for a long time. This is different to magnesium, for example, which tarnishes when in contact with oxygen.
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29. Bonding
When atoms react together, they usually form bonds and combine. A chemical bond is a mechanism that chemically combines atoms.
There are two main types of bonding:
Chemical bond
Ionic
A + B AB
Covalent
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30. Ionic Bonding
Ionic bonding involves the complete transfer of electrons from one atom to another.
This causes the formation of oppositely charged ions. One atom loses electrons and becomes positively charged. The other gains electrons and becomes negatively charged.
The oppositely charged ions are held together due to the attraction between two opposite charges.
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31. Ionic Bonding Sodium chloride is a good example.Na Cl
Sodium chloride is a good example.
Sodium has one electron in its outer energy level, and chlorine needs one electron to have a complete outer energy level.
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32. Ionic Bonding Na
Na+
Cl- Cl + -
Na + Cl NaCl
Therefore, when sodium and chlorine react, each sodium atom loses one electron and forms a positive ion. Each chlorine atom gains one electron and forms a negatively charged ion.
The ions are held together as opposite charges attract. This ionic bond makes the compound sodium chloride.
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33. Shared electrons due to overlap of energy levels
Covalent Bonding A B B A
Single Bond
Shared electrons due to overlap of energy levels
Covalent bonding involves the sharing of electrons, rather than their complete transfer.
The outer electron energy levels overlap, sharing the electrons between the atoms.
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34. Covalent Bonding A B B A
Double Bond
One pair, two pairs, or even three pairs of electrons can be shared, forming single, double, or triple bonds.
This type of bonding usually occurs between non-metallic elements.
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35. Covalent Bonding An example is chlorine gas, Cl2.
Each chlorine atom has seven electrons in its outer energy level. However, it needs eight to be a completely full level.
One electron from each atom is donated to form a pair of electrons. The pair of electrons is shared between both atoms. This bond holds them together. Cl
It is called a single covalent bond.
Single covalent bond
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36. Question 4
“Covalent bonding involves complete transfer of electrons from one atom to another.”
Is this statement true or false?

37. Question 4
“Covalent bonding involves complete transfer of electrons from one atom to another.”
Is this statement true or false?
False
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38. Summary In this presentation you have seen:
that each element has a different reactivity.
the trends in reactivity within the halogens and alkali metals.
the difference between ionic and covalent bonding.
End