1 Elements and their atoms
description
Transcript of 1 Elements and their atoms
![Page 1: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/1.jpg)
1 Elements and their atoms
• Each element of the Periodic table is built from one type of atom• Atoms have a nucleus containing
protons and neutrons, surrounded by electrons within energy levels (shells).
![Page 2: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/2.jpg)
2 Elements in groups
• Elements in the same group of the Periodic table have the same number of electrons in the highest energy level (outer shell).• Elements in the same Group react in similar ways.
![Page 3: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/3.jpg)
3 Equations
• Balanced equations describe reactions.• The reactants are on the left and the products are on the righte.g. CuO + CO = Cu + CO2copper oxide + carbon monoxide = copper + carbon dioxide
![Page 4: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/4.jpg)
4 Cement and concrete• Limestone is heated with clay to
form cement. • Cement, water, gravel and sand
form concrete.
![Page 5: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/5.jpg)
5 Metal carbonate decomposition• Metal carbonates are
decomposed by heat to form metal oxides plus carbon dioxide.e.g. CaCO3 → CaO + CO2
• Calcium carbonate decomposes into calcium oxide and carbon dioxide• This is done in lime kilns.
![Page 6: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/6.jpg)
6 Calcium oxide and hydroxide
• Calcium oxide reacts with water to form calcium hydroxide.
• Calcium hydroxide solutions reacts with carbon dioxide to form calcium carbonate. This is the test for carbon dioxide.
![Page 7: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/7.jpg)
7 The ‘Lime’ cycle
![Page 8: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/8.jpg)
8 Transition elements• The elements in the middle of Periodic table are called transition metals.• They include metals in common use such as copper and iron
![Page 9: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/9.jpg)
9 Transition elements• Transition metals are hard, strong
and have coloured compounds
![Page 10: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/10.jpg)
10 Alloys• Pure iron is converted into an alloy (steel) by mixing it with other elements. • This alters the arrangements of atoms.
![Page 11: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/11.jpg)
11 Pure metal & alloy structures
• Pure iron is softer than its alloy, steel.• In pure iron the
layers of atoms can slide over each other easily.• In steel, small
atoms of carbon disrupt the layers and prevent sliding.
![Page 12: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/12.jpg)
12 Extracting metals from their ores
• Metals are extracted from ores by electrolysis, or heating and reacting with carbon.• This is called reduction.
![Page 13: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/13.jpg)
13 Aluminium and titanium• Aluminium and titanium have low
densities and do not corrode. • They are extracted using
expensive electrolysis.• Recycling metals saves resources,
energy and waste.
![Page 14: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/14.jpg)
14 What is crude oil?• Crude oil is a non-renewable resource. • It is a mixture of hydrocarbons • It is separated by fractional distillation.
![Page 15: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/15.jpg)
15 Alkane hydrocarbons• Alkanes are a family of saturated hydrocarbons • Saturated hydrocarbons contain only single covalent bonds. • Alkanes have the general formula CnH2n + 2
![Page 16: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/16.jpg)
16 Products of combustionBurning hydrocarbon fuels releases harmful substances:• carbon dioxide (greenhouse
effect); • carbon monoxide (toxic); • sulphur oxides and nitrogen
oxides (acid rain) and, • particulates (global dimming).
![Page 17: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/17.jpg)
17 Biofuels• Biofuels (biodiesel, bioethanol)
are produced from plant material. • Producing biofuels releases less
carbon dioxide overall and uses renewable resources. • It may reduce the amount of
food crops the world can grow.
![Page 18: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/18.jpg)
18 Cracking• Cracking using heat and a catalyst breaks down long chain alkanes into smaller molecules including alkenes.• Cracking helps to produce more lighter oils which are in demand.
![Page 19: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/19.jpg)
19 Alkene hydrocarbons• Alkenes are unsaturated
hydrocarbons which contain C=C double bonds.• Alkenes have the general
formula CnH2n . • Bromine water is used to test
for C=C double bonds. Alkenes decolourise bromine water.
![Page 20: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/20.jpg)
20 Making polymers• Alkenes are used to manufacture polymers. • In polymerisation reactions many smaller monomer molecules join to form one large polymer molecule.
![Page 21: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/21.jpg)
21 Polymers• Polymers may have a wide range of properties. • The uses of a polymer depend on its properties.e.g. poly(ethene) for plastic bagsand poly(vinylchloride) for electrical wire insulation
![Page 22: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/22.jpg)
22 Biodegradable?• The disposal of non-
biodegradable polymers causes environmental problems.• Microbes cannot break the
polymer molecules down when they are buried in landfill sites.• Electrical wire insulation cannot
be broken down either (phew).
![Page 23: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/23.jpg)
23 Ethanol from fermentation
• Ethanol is a molecule which can be formed from renewable resources (fermentation of sugars).• Ethanol can be formed from
non-renewable resources (ethene and steam).
![Page 24: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/24.jpg)
24 What are plant oils like?• Plant oils have a high energy
content• Plant oils have high boiling points• Plant oils can be used in cooking.• This fried food has lots of extra
energy that may lead to weight gain and heart problems in the long term.
![Page 25: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/25.jpg)
25 Margarine • Plant oils can be hardened into margarine, a solid fat.• The plant oil is made to react with hydrogen (hydrogenation).• This process uses a nickel catalyst that speeds up the rate of production.
![Page 26: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/26.jpg)
26 Extracting plant oilsPlant oils can be extracted from plant material by:1)pressing, 2)solvent extraction
followed by3)distillation, or steam
distillation (for delicate oils).
![Page 27: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/27.jpg)
27 Emulsions, ice cream & mayo
• Plant oils do not dissolve in water• They can be made into emulsions.• This involves the use of emulsifiers, for example, egg is used in the manufacture of mayonnaise from oil and vinegar
![Page 28: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/28.jpg)
28 The Earth is made of layers
• The Earth has a layered structure. • Thick rocky crusts float on the mantle.• Its centre is the hot iron core.
![Page 29: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/29.jpg)
29 Tectonic plates• The crust is divided into
tectonic plates. • Convections currents in the
mantle cause the plates to move.• Earthquakes and volcanic
eruptions occur at plate boundaries.
![Page 30: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/30.jpg)
30 Atmosphere• The Earth’s atmosphere has a
stable composition.• 78% nitrogen
21% oxygen, with small quantities of other gases including carbon dioxide
![Page 31: 1 Elements and their atoms](https://reader036.fdocuments.in/reader036/viewer/2022081507/568165f9550346895dd9279e/html5/thumbnails/31.jpg)
31 Earth’s early atmosphere
• The early atmosphere of the earth was mostly carbon dioxide and water vapour• There were small amounts of ammonia and methane.