1. Standard Grade Topics 3 &4

2. Standard Grade Revision Units 3 and 4 Answer:- (a) Lithium Q1. The box below shows the names of some elements. neon.lithiumchlorine oxygencopperargon (a)Identify the alkali metal. (b)Identify the halogen. (c)Identify the element with the highest melting point. (d)Identify the two very unreactive elements. (e) Identify the two elements which exist as diatomic molecules. (b) Chlorine(c) Copper (d) Neon and argon(e) Chlorine and oxygen. Use your data booklet.

3. Units 3 and 4 Revision Q2. The box below shows the names of some elements. sulphur mercurycarbon plutonium brominesodium Identify the element which (a) is a liquid non-metal at room temperature. (b) is in group 4 of the Periodic table. (c) is radioactive. (d) has an electron arrangement of 2,8,6 (e) is a liquid metal at room temperature. (f) is man-made. Answers:- (a) bromine(b) carbon.(c) plutonium (d) sulphur(e) mercury(f) plutonium Use your data booklet. Standard Grade Chemistry

4. Q3. Identify the element in group 1 that produces a red flame colour. Q4. Explain why the metal elements in group 1 are (a) called the alkali metals. (b) stored under oil. Q5. What happens to the melting point of the elements in group 7 (the halogens) as you go the group? Units 3 and 4 Revision Answers:- Q3. Lithium. Q4. (a) The elements in group 1 react with water to form an alkaline solution. (b) The elements in group 1 are stored under oil to stop them reacting with oxygen in the air, Use your data booklet. Q5. The melting point increases. Standard Grade Chemistry

5. Units 3 and 4 Revision. Q6. Which of the sub-atomic particles in an atom is being described? (a) Mass of 1 amu and a charge of 0. (b) Mass of almost zero and a charge of 1-. (c) Mass of 1 amu and a charge of 1+. Q7. An atom of aluminium can be shown as 27 Al 13 (a) What is the mass number of this atom? (b) What is the atomic number of this atom? (c) How many (i) protons (ii) neutrons (iii) electrons are there in this atom? (d) Explain why this atom is neutral. (a) neutron (b) electron (c) proton. (a) 27 (b) 13 (c) (i) 13 (ii) 14 (iii) 13 (d) Same number of protons (+ ) and electrons (-) Standard Grade Chemistry

6. Units 3 and 4 Revision. Q8. Identify the element (a) with an atomic number of 12. (b) with an electron arrangement of 2,5 (c) which has 9 electrons in its atoms. Q9. Explain why the elements lithium, sodium and potassium have similar chemical properties. Q10. Chlorine atoms exists as two different isotopes 35 Cl and 37 Cl. The relative atomic mass of chlorine is 35.5 (a) What is meant by the term ‘isotopes’? (b) Which of the two isotopes is there more of in chlorine? (a) Magnesium (b) Nitrogen (c) Fluorine These elements have the same number of electrons in their outer energy level – this gives them similar properties. (a)Atoms with same atomic number and different mass number. (b) 35 Cl isotope is more common. Use your data booklet. Standard Grade Chemistry

7. Units 3 and 4 Revision. Q12. Write the formula of the following compounds. (a) Sulphur trioxide. (b) Dinitrogen monoxide (c) Phosphorus pentachloride. Q13. Write the formula of the following compounds. (a) Sodium sulphide. (b) Aluminium oxide. (c) Silicon oxide. (d) Iron(III) chloride. Q14. The box below gives the names of some compounds. magnesium bromide sodium bromide lithium hydroxide sodium iodide potassium sulphate lithium chloride Identify the compound with the formula XY 2 where X is a metal. SO 3 N 2 O PCl 5 Na 2 S Al 2 O 3 SiO 2 FeCl 3 Magnesium bromide (MgBr 2 ) Standard Grade Chemistry

8. Units 3 and 4 Revision. Q15. Hydrogen reacts with oxygen to form water. This reaction is shown by the following equation which is not balanced. H 2 + O 2  H 2 O Rewrite this as a balanced equation. Q16. Iron(III) oxide reacts with carbon monoxide to form iron and carbon dioxide. This reaction is shown by the following equation which is not balanced. Fe 2 O 3 + CO  Fe + CO 2 Rewrite this as a balanced equation. Fe 2 O 3 + 3CO  2Fe + 3CO 2 2H 2 + O 2  2H 2 O Standard Grade Chemistry

9. Units 3 and 4 Revision. Q17. The box below shows a number of gas elements. argonhydrogenfluorine neonnitrogenoxygen (a) Identify the gas which contains diatomic molecules bonded together by a double covalent bond. (b) Identify the two gas which contains single atoms (monatomic) (a) Oxygen. (b) Argon and neon. Standard Grade Chemistry

10. Q11. In a hydrogen molecule the atoms share two electrons in a covalent bond. (a)Explain how the covalent bond holds the two hydrogen atoms together. (b)The hydrogen molecule can be represented more simply as (i) Showing all outer electrons, draw a similar diagram to represent a molecule of ammonia, NH 3. (ii) Draw another diagram to show the shape of an ammonia molecule. (a) The negatively charged electrons in the bond are attracted to the positively charged protons in the nuclei of the hydrogen atoms. (b) (i) H (ii) H: N:N H H H H.. Standard Grade Chemistry