1000 contains 2 elements; usually metal and non …...atoms, elements, compounds and mixtures part 1...

Atoms, elements, compounds and mixtures PART 1 – QuestionIT

1. Around how many different types of elements are there in the periodic table?1000

2. What does it mean if a compound ends in –ide?Contains 2 elements; usually metal and non-metal.

3. What does it mean if a compound ends in –ate?Contains 3 or more elements, 1 of which is always oxygen.

4. What does a chemical reaction involve?The formation of one or more new substances; usually with an

energy change.5. Name the following substances:• NaCl Sodium chloride.• NaSO4 Sodium sulfate.


6. Why is it useful to have symbols for atoms of different elements?When elements join together to form a compound, it tells you how many atoms there are.

7. What is the difference between an element and a compound?Elements contain one type of atom and compounds contain more than one type.

8. Why is it difficult to separate a compound?A compounds elements are chemically joined together.


9. Solid sodium reacts with water to form a sodium hydroxide solution and hydrogen gas.

a) Write a word equation to represent this reaction.Sodium + water à sodium hydroxide + hydrogen

b) Give the balance symbol equation for the reaction.2Na(s) + 2H2O(l) à 2NaOH(aq) + H2(g)

HT only:10. When magnesium reacts with sulfuric acid, the hydrogen ions in

the acid will be displaced from the solution by magnesium.Balance the following ionic equation.

Mg(s) + 2H+(aq) à Mg2+(aq) + H2(g)


1. What is the difference between a compound and a mixture?The substances in a mixture are not chemically bonded together, but they are in a compound.

2. Describe the method used to collect the salt from a mixture of sand and salt.Add water and stir to dissolve the salt. Use filtration to remove the sand. Heat the water (gently) to allow the salt to crystallise (to avoid dryness).

3. What process is used to purify seawater to obtain usable water?Simple distillation.


4. Describe how the following equipment is used to separate water and ethanol.

The ethanol and water mixture are heated. Ethanol has a boiling point of 78°C and will vaporise first. The gas passes over the fractionating column and into the condenser. Here it will condense, turning back into it’s liquid state.


5. A mixture and six colours are tested using chromatography. The following chromatogram was produced:

a) What can you conclude about the mixture?The mixture is made up from substance 1 and 4.

b) Why do the inks separate to produce a chromatogram?The separation depends on how soluble the chemical is in the solvent and how strongly the chemical is attracted to the paper.

Atomic model PART 1 – QuestionIT

1. What was the earliest model of the atom?Tiny spheres that could not be divided.

2. Which subatomic particle did JJ. Thomson discover?The electron

3. Which early atomic model does the following diagram show?The plum pudding model.

4. Name Rutherford’s experiment. Alpha particle scattering.

5. State two ways in which Rutherford’s experiment changed Thomson’s model of the atom.

He said the positive charge was concentrated into very small volume at centre of atom (nucleus) and the electrons orbit nucleus.


6. Explain why Bohr revised Rutherford’s model of the atom.Suggesting electrons orbit the nucleus at different distances.

7. Explain why Bohr revised Rutherford’s model of the atom.Energy emitted from electron transitions can only have certainfixed energies, so he refined the ‘orbiting electrons’ inRutherford’s nuclear model to ‘orbiting electrons in energy levels(or shells) at fixed distances from the nucleus’.


1. Name three subatomic particles and their charges.Proton – positive; neutron – no charge; electron – negative.

2. Complete the sentence ‘All atoms of one type of element have the same number of…’Protons.

3. What does the atomic number tell us about an atom?Number of protons.

4. What does the mass number tell us about an atom?Number of protons + number of neutrons.

5. How is an isotope different to an atom?Different number of neutrons.

6. What is the electron configuration for sodium?2,8,1


7. Why is the overall charge of an atom zero?Number of protons (positive) = number electrons (negative).

8. Draw the electron configuration for a chlorine atom.

9. Write the electron configuration for potassium.2,8,8,1

10. How many electrons does potassium have on its highest energy level?1


11. Calculate how many protons, electrons and neutrons there are in:a) A silver atom with atomic number 47 and mass number 108Protons = 47 Electrons = 47 Neutrons = 61b)

Protons = 19 Electrons = 18 Neutrons = 20

12. The atomic radius of a bromine atom is 9 x 10 -11ma) Give its atomic radius in nanometres.

0.09 nm

b) Calculate the radius of the nucleus (in nm), given that it will be about 1/10,000 the radius of the atom. Give your answer in standard form.9 × 10−6nm

Periodic table PART 1 – QuestionIT

1. How are elements arranged in the modern periodic table?

Increasing atomic number.

2. What are the columns of the periodic table called?

Groups.

3. What are the rows of a periodic table called?

Periods.

4. What does the column an element is in tell you about the atoms?

Number of electrons in outer shell.

5. What does the row an element is in tell you about the atoms?

Number of electron shells.


6. Which side of the periodic table are the non-metals found?

Right and top.7. How were elements classified before the discovery of subatomic

particles?Arranging in order of their atomic weights.

8. What was the problem with early periodic tables?

Incomplete; some elements placed in inappropriate groups.

9. How did Mendeleev overcome these problems?Left gaps for elements he thought had not yet been discovered; changed the order based on atomic weights for some elements if they did not fit the pattern.


10. Why is the order based on atomic masses not always correct?

The presence of isotopes.

11. What do we call elements that tend to form positive ions?

Metals.


1. What are the elements in Group 0 called?Noble gases.

2. What are the elements in Group 1 called?Alkali metals.

3. What are the elements in Group 7 called?Halogens.

4. What happens to the boiling point of elements in Group 0 as you go down the group?Increase.

5. Why are the elements in Group 0 so unreactive?Full outer shell of electrons.

6. Why do all elements in Group 1 react in a similar way to each other?1 electron in outer shell.


7. What happens to the reactivity of the elements as you go down Group 1?Increases.

8. Write a word equation for the reaction between sodium and oxygen.sodium + oxygen à sodium oxide

9. Why do all the elements in Group 7 react in a similar way to each other?7 electrons in outer shell.

10. Halogens are diatomic. What does the word ‘diatomic’ mean?There molecules contain 2 atoms.

11. What happens to the reactivity as you go down Group 7?Decreases.


12. What happens to the melting point and boiling point as you go down Group 7?Increases.

13. Write a word equation for the reaction between lithium and chlorine.lithium + chlorine à lithium chloride

14. Write a balanced chemical equation for the reaction between lithium and chlorine gas.2Li(s) + Cl2(g) à 2LiCl(s)

Bonding PART 1 – QuestionIT

1. What are the three types of strong chemical bond?Ionic, covalent, metallic.

2. What particles are found in:a) Ionic bonding oppositely charged ions.b) Covalent bonding atoms which share electrons. c) Metallic bonding? Atoms which share delocalised electrons.

3. Which type of bonds occurs when metals combine with non-metals?Ionic.

4. What type of bonding occurs in carbon dioxide? Why?Covalent; two non-metals.

5. What type of bonding occurs in alloys?Metallic.


6. What happens to the electrons in ionic bonding?Transferred.

7. What electronic structure do the ions produced by metals in Groups 1 and 2 and the non-metals in Groups 6 and 7 have?Electronic structure of a noble gas.

8. What is the link between the charge number on the ions in groups 1, 2 and 3 and their group number ? Charge number is same as Group number.

9. What is an ionic compound? Giant structure of ions.

10. How are ionic compounds held together?Strong electrostatic forces of attraction; between oppositely charged ions.


11. Why is the ball and stick model not an accurate representation of the structure of an ionic compound? Does not accurately depict the millions of ions in the lattice. The ions should touch each other/ there are no gaps between the ions.

12. Draw a diagram to show how potassium and chlorine atoms join together to form ions.

Ionic bonding PART 2 – QuestionIT

13. Explain how you can use the following model of sodium chloride to work out the empirical formula.

Count the number of each type of atom in the giant structure and work out simplest whole number ratio.

Bonding – Part 2 – QuestionIT

1. How are strong covalent bonds formed?Atoms share pairs of electrons.

2. What are the three types of structure that can be formed by covalent bonding?Small molecules, very large molecules, giant covalent molecules.

3. What are polymers an example of?Very large molecules.

4. What type of structure do the following covalently bonded substances have?a) Water H2O Small covalent.b) Silicon dioxide SO2 Giant covalent.c) Diamond C Giant covalent.d) Poly(ethene) Very large molecule.

Bonding – Part 2 – QuestionIT

5. What are the limitations of using dot and cross diagrams to represent covalent bonds?It shows the electrons differently, when they are the same and it does not show the bond angles or shape of the molecule.

6. How are atoms arranged in a metal?Giant structures of atoms, arranged in a regular pattern, delocalised electrons.

7. Why are metallic bonds so strong?Sharing of delocalised electrons.

8. What is the formula of the following model?CO2

Bonding – part 2 – QuestionIT

9. Draw a dot and cross diagram for water.

10. Describe the arrangement of particles in a metal.Atoms arranged neatly in rows; sea of delocalised electrons.

11. Why are the particles that make up a metal described as positively charged?The metal atoms lose outer shell electrons and therefore there are more protons (+) than electrons (−).

12. What are delocalised electrons?They are free-moving electrons within structure; not associated with a particular atom.

Properties of substances – Part 1– QuestionIT

1. What are the three states of matter?Solid, liquid, gas.

2. What is used to represent particles in the simple particle model?Small solid spheres.

3. What takes place at the melting point?Melting and freezing.

4. What takes place at the boiling point?Boiling and condensing.

5. What factor affects the amount of energy needed to change state?Forces between molecules.


6. In chemical equations what symbols are used to show the states of matter? Solid = (s); liquid = (l); gas = (g); aqueous = (aq)

7. In what state of matter do particles have the most energy?Gas.

8. What would eventually happen to a gas if pressure is increased?Condense into a liquid.

9. HT ONLY: Explain the limitations of the particle model.No forces, particles are shown as spheres, spheres are solid.


10. The following represents the heating of ice:

a) What change in state happens at stage 2?

Melting/ freezingb) What is happening at

stage 4?Boiling/ condensing

Properties of substances – Part 2 – QuestionIT

1. Describe the structure of ionic compounds.Regular, giant ionic lattice.

2. Why do ionic compounds have high melting and boiling points?Strong electrostatic forces of attraction between ions.

3. Why can ionic compounds conduct electricity when melted or dissolved in water?Ions are free to move, carry the charge.

4. What state of matter are small molecules normally found in?Gas or liquid.

5. Why do small molecules have low melting and boiling points?Weak forces between molecules/ intermolecular forces.


6. What happens to the melting and boiling points as small molecules get bigger? Why?Increases, intermolecular forces get bigger.

7. Why don’t small molecules conduct electricity?Do not have an overall electric charge.

8. What are polymers?Very large molecules made of repeating units.

9. How are the atoms in a polymer linked together?Strong covalent bonds.

10. Why are polymers normally solid at room temperature?Intermolecular forces relatively strong.

11. Give an example of a giant covalent structure.Diamond, graphite, silicon dioxide.


12. Why do giant covalent structures have very high melting and boiling points?Strong covalent bonds must be broken.

13. Why do most metals have high melting and boiling points? Strong metallic bonding.

14. How are atoms arranged in pure metals?Layers.

15. What is an alloy?Mixture of two elements, one of which is a metal.

16. Why do we use alloys, rather than pure metals, for many uses?They are harder as the layers are distorted.


17. Why are metals good conductors of electricity?Electrical charge carried by delocalised electrons.

18. What is thermal energy?Heat energy.

19. Why are metals good conductors of thermal energy?Energy is transferred by delocalised electrons.


1. In a diamond, how many covalent bonds does each carbon make?4

2. Diamond does not conduct electricity. Why?No delocalised electrons.

3. Name 2 other properties of diamond.Hard, very high melting point.

4. In graphite, how many covalent bonds does each carbon make?3

5. Describe the structure of graphite.Layers of hexagonal rings.

6. Why is graphite soft?Layers can slide over each other, weak forces between layers, no covalent bonds between layers.


7. Why does graphite conduct electricity?Each carbon has one delocalised electron.

8. How is graphite similar to metals?It contains delocalised electrons.

9. What is graphene?Single layer of graphite, 1 atom thick.

10.What are fullerenes?Molecules of carbon atoms with hollow shapes.

11.What was the first fullerene to be discovered?Buckminsterfullerene.

12.What are carbon nanotubes?Cylindrical fullerenes.

13.What are carbon nanotubes useful for?Electronics, nanotechnology and materials.

1000 contains 2 elements; usually metal and non …...atoms, elements, compounds and mixtures part 1...

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