Year 8 (Stage 4) History and Symbols of Elements and Periodic Table.

Elements Compounds and Mixtures- History of Elements and Chemical Symbols

Download this file: Yr 8 Elements and Symbols

Part (A) – Elements and the Chemical Symbols  (Reading)

WHAT IS AN ELEMENT?

A substance that cannot be broken down into simpler substances by chemical reactions. Atoms of the elements are identical. All atoms of the same element have the same physical properties (size of the atom) and the same chemical properties. Scientists arranged all the elements they knew or they discovered in a periodic table.

 

SYMBOLS of ELEMENTS:  

A chemical symbol (or a chemical formula)  is a shorthand method of representing an element. Instead of writing out the name of an element, we represent an element name with one or two letters. The periodic table is a chemist’s easy reference guide.

The symbols used by earlier scientists (Dalton and other scientists in 1808 – 1815) are quite different from symbol that appeared in the periodic table published by Mendeleev   1861, scientists used to obtained the modern periodic table.

 

Part B: WHAT YOU ALREADY KNOW about the SYMBOLS of elements in a periodic table.

  1. A capital letter H or a small letter h is used to represent Hydrogen?
  2. The symbol for chlorine is cl or Cl or CL?
  3. The symbol for carbon is c or C?
  4. The symbol for helium is He or HE or he?
  5. The symbol for calcium is Ca or CA or ca? Why can’t we use C instead?
  6. The symbol for lead is le or LE  or Pb and PB? Why? Explain your answer.
  7. The symbol for  mercury is me or Me or ME or Hg or HG or hg? Why? Explain your answer.
  8. The symbol for  gold is go or Go or GO or Au, or AU?  Why? Explain your answer.
  9. The symbol for silver is  si  or Si or SI or Ag, or AG? Why? Explain your answer.
  10. The symbol for  iron is  ir or Ir or IR  or FE , or Fe? Why? Explain your answer.


PART C: INVESTIGATIONS:
– Answer all the questions below:

  1. What is the definition of an element?
  2. What are chemical symbols and why are they used?
  3. Use the links below to complete the table below:
  • Use the  periodic table to find out the symbols of the elements.
  • Use the periodic table to find out whether they are metals, non-metals or metalloids.
  • Use the periodic table to find out whether the elements are solids,  liquids or gases at room temperature.

 

 

Number Name of element Chemical Symbol Solids, liquids or gases at room temperature Metals, non-metals or metalloids.
1 hydrogen
2 He
3 Lithium
4 Be
5 Boron
6 C
7 Nitrogen
8 O
9 9luorine
10 Neon
11 Na
12 Magnesium
13 Aluminium
14 Si
15 P
16 S
17 Chlorine
18 Argon
19 Sodium
20 Potassium
21 iron
22 Copper
23 iron
24 gold
25 silver
26 Mercury
27 lead
28 tungsten
29 Nickel
30 Arsenic

 

 

Questions

  1. Name all elements that are metals in the above table?
  2. Name all elements that are  non-metals in the above table?
  3. Name all elements that are metalloids in the above table?
  4. True or false?
  1. Metals can conduct heat and electricity easily.    T/F
  2. Metals are shiny?   T/F
  3. Non-metals can conduct heat and electricity easily.   T/F
  4. Non- metals are dull.   T/F
  5. Non-metals are found on the left of the periodic table? T/F
  6. Metals are found on the right of the periodic table? T/F
  1. What is the symbol tungsten (usd to make filament of lamp?

 

Part E   Research.   (Group work) and presentation.  

Choose an element in the table above (one element per student in the group) and answer the questions below. Prepare a minute presentation per student in the group.

 

Name of element: _____________________ researched by _____________ (student name.

 

  1. What is the chemical symbol of this element? Why is it given this symbol (your reason for this)?
  2. Who discovered/worked with the element?
  3. Where and when is this element found naturally?
  4. Name two uses of this element.

 

 

Year 11 Physics – Electricity and Electromagnetism- Static Electricity

RUBBING YOUR SHOES ON CARPET CAN “ZAP” YOU. WHY?

 STATIC ELECTRICITY

The ancient Greeks discovered that rubbing amber with fur or other objects, it could pick up things like feathers! They may have discovered electricity. Electricity comes from the Greek word elector, which means ‘beaming sun’. This name came about because amber had a rich yellow glow in the sunlight.

 Have you had any of these experiences?

  • You walk to the tap to have a drink. Zap~
  • You put a jacket over your nylon team jumper. Zap~
  • Here comes mum in the car, and you touch the car door handle. Zap~
  • Even at home the carpet can zap you~

 

Static electricity is made when materials rub together. The more they rub together, the more electricity is made. This means bigger sparks. When you rub or brush a rod with a cloth, you rub off electrons. Having too many electrons makes a negative charge, and having too few electrons makes a positive charge. A spark is formed when electrons jump from where there are too many electrons to where there are too few.

The study of static electricity forces is called electrostatics. An uncharged plastic rod has an equal number of positive and negative charges. The negative charges are called electrons. Because they are at the edge of the atoms, electrons are easy to rub off. When you rub or brush a rod with a cloth, you rub off electrons. Sometimes the electrons are rubbed off the rod onto the cloth. And sometimes the electrons are rubbed off the cloth onto the rod.

Static electricity occurs with many non-metal materials. There is an electric field around objects which have an electric charge.

Year 8 (Stage 4) Elements Compounds and Mixtures- Survey and History of Atoms.

Elements Compounds and Mixtures- 1.What are the early ideas of atom?

Download the word document: Survey and History of Atoms:  Yr 8 Element C M_Survey and history of atoms

WHAT YOU ALREADY KNOW – Survey

Part (A) What you already know- Survey and Discussion.

Answer the questions below:

  1. Matter are made up of tiny particles called atoms.     T/F
  2. All atoms in one matter have the same size and mass. For example, atoms of iron are all of same size and mass.
  3. All atoms of iron have the same chemical properties e.g. rusting  T/F
  4. Atoms in different matter are different in size and shape. For example, atoms of iron are different from atoms of another metal such as magnesium.   T/F
  5. Atoms are always in motion (either vibrating or moving around).  T/F
  6. Rusting of iron is a chemical reaction.    Y/N
  7. Water is a chemical.   T/F
  8. Oxygen is a chemical   T/.F
  9. Do you know what is an element?     Y/N
  10. Do you know what is a compound?    Y/N
  11. Oxygen is an element?    T/F
  12. Do you know all chemicals listed on the periodic table are elements?  Y/N
  13. Water is made up of two elements listed on the periodic table. Name these two elements.       _________ and ________
  14. Do you know the formula for water?   Y/N     Write down the formula for water: _____
  15. Do you know water is not an element but a compound?    Y/N     Do you know why  Y/N
  16. Have you heard about protons, neutrons, electrons?    Y/N
  17. Rocks and minerals are chemicals?   T/F
  18. Gold and copper are minerals and are elements and are listed in the periodic table. .    T/F
  19. Do you know that pencil lead is made from the element, carbon?   Y/N
  20. Carbon dioxide is made when two elements, carbon and oxygen combined in a chemical reaction.   Y/N

PART (B)  HISTORY of ATOMS  – What were the early ideas? Who

HISTORY OF ATOMS – What were the early ideas of atoms?

 

Democritus (460-370 B.C.) Ancient Greece

His ideas of atoms:

 

  1. Matter was made up of tiny solid particles he called atomos.
  2. Different matter is made up of atomos that have different size and shape,
  3. Changes in matter are caused by a changing of the grouping of atomos, not in changing the atomos themselves.

 

Main idea:  Democritus introduce the idea that matter is made up of atoms. All atoms of same matter are identical. Atoms of different matter are different.

 

 

Dalton, England:  (1803) Ideas of atom:

 

  1. Atoms are solid spheres.
  2. Each atom has a mass.
  3. Atoms of same elements have the all same mass.
  4. Atoms are rearranged in a chemical reaction
  5. Compounds are formed when two or more different kinds of atoms join together.

 

 

Main idea:

Atoms of same elements have the all same mass, atoms can be rearrangeed in a chemical reaction to form compounds.

 

JJ Thomson:  (1897)  

 

  1. He discovered the electron in 1897.
  2. His idea showed  that the atom contained smaller pieces, whereas Dalton had thought that atoms could not be broken down into anything simpler.
  3. His experiment using a cathode ray tube provides more thorough understanding of the properties of an electron (its mass compared with its electrical charge) and its properties.

 

 

Ernest Rutherford’s nuclear atom  (1911)

 

 

  1. Ernest Rutherford used experimental evidence to show that an atom must contain a central nucleus.
  2. Rutherford assumes that electrons are located outside the nucleus.
  3. This was further evidence that an atom contained smaller particles called subatomic particles
  4. This experiment introduces the nucleus and its properties, and shed more light on the contents of the atom.

 

Bohr’s electron orbits  (1922)

  1. Niels Bohr further developed Rutherford’s nuclear atom model. He used experimental evidence to support the idea that electrons occupy particular orbits or shells around the nucleus of an atom.
  2. The development of the theory of atomic structure is an example of:
  • How a theory may change as new evidence is found
  • How a scientific explanation is provisional but may become more convincing when predictions based on it are confirmed later on

 

 

Year 8 (Stage 4) Elements, Compound and Mixtures – Inquiry Questions

 

Inquiry Questions
1.What are the early ideas of atom (particle theory/kinetic theory of particles)?
2. What is the smallest unit of an element?
3. What is an element?

How scientists derived symbols for the elements for the first twenty on the periodic table.

What are the symbols of other transition metals – Zinc , Iron , Silver, Gold, Mercury?

 

4. How elements are classified as metals, non-metals and metalloids on a periodic table?

Do elements in the same group have the same properties?

5. Where are groups 1 and 2 and group 3 and 4 located on the periodic table?

Are groups 1 and 2 metals? Are groups 7 and 8 non-metals?

Which of the elements are gases and solids at room temperature?

6. Where are the subatomic particles –protons, neutrons and electrons (these are smaller than atom) located in an atom? Who discovered these subatomic particles and what technological devices assisted in their discoveries?
7. How the subatomic particles (protons, neutrons and electrons) arranged within the atom e.g Helium atom?
8. How can scientist tell the difference between elements, compounds and mixtures?
9. How models can be used to show the difference between molecules e.g. monoatomic (Helium), diatomic H2, metallic, chains (C3H8). How models can be used to compare structure and diamond?
10. Are these everyday substances such as water, sugar, tea, air, blood and bread classify as elements, compounds or mixtures? What are the composition of each of these substances?
11. Can Hoffmann voltameter show that water is a compound and that it can be decomposed to form oxygen and hydrogen?

Can a new compound be made by heating magnesium in a flame?

12. What are uses and special properties of the ten substances that changed the world? Research the five compounds that changed the world? In which cultures are these materials used?
13. What are the useful properties of silica that allows it to be used in optical fibres? How the optical fibres are used in endoscope and optical fibre communications?
14, What are the reasons for using polymer money in Australia?
15. Is there a need to continually develop new pharmaceuticals? Why should scientists be encouraged to do research into these products?

Electrostatics- Summary

Static Electricity – Summary

  1. Static means ‘still’ and is the word we use when we talk about the charge that can’t move. A good example of this is when you rub a balloon on your hair and it sticks to the ceiling. You use friction  to charge up the balloon.
  2. There are two kinds of charge: positive (+) and negative (-).
  3. All objects are made up of atoms, and all atoms contain positive particles (protons) and negative particles (electrons).
  4. And yet atoms don’t have an overall charge. They are neutral.
  5. That’s because atoms contain the same number of protons and electrons. So the positive and negative charges are cancelled out.
  6. Static electricity is caused by an atom having too many or too few electrons (e-).
  7. When insulating materials are rubbed together, electrons are knocked off one of them and onto the other.
  8. This happens when a perspex strip is rubbed with a duster, the electrons move from the duster to the strip. The strip becomes negative (because it has more electrons than it needs to cancel out the protons) and the cloth becomes positive because it has fewer electrons than it needs).
  9. The way you may have seen static generated at school is with a Van de Graaff Generator (see diagram). The motor turns the rubber band and friction between the band and the rollers starts to build up huge amounts of charge.   
  10. This charge is then deposited on the metal dome, which is a charged but is insulated from everything else (like birds sitting on a power line), so it is able to store the charge.
  11. Metals are good conductor while non-metals are insulators.
  12. Basic rules:   Like charges repel.             AND          Opposite charges attract_. 

  13. An atom is made up of two parts – a positively charged nucleus surrounded by negatively charged electrons. In an uncharged (neutral) atom, there is the same number of positive and negative charges.

  14. The charge can build up in a big way, causing voltages as high as 50,000 Volts. A shock_ from this doesn’t kill you, as the actual amount of charged particles stored on the dome is so small.

MAIN POINTS:

 1. Two types of charges: positive and negative. 

2.

 Attractive force exists Repulsive force exists
A positively charged object and a negatively charged object. A positively charged object with another positively charged object.
        A neutral object and a positively charged object. A negatively charged object with another negatively charged object.
A neutral object and a positively charged object.

3. Objects with no charge do not attract each other. A comb that is not charged will not pick up pieces of paper.   Objects which are charged can pick up pieces of paper.