Download the presentation here Download Notes & WorksheetsAtomic Structure & Chemical Bonding Notes (Credits to Mustafa Asif) (Thanks to a contributor!) SummaryNuclear model of an atom
Electronic Configuration
Relation with Periodic Table
Structure of Mattera. Atom: Smallest particle of an element b. Molecule: group of two or more atoms chemically joined together, e.g. chlorine molecule has 2 chlorine atoms Classifying elements
d. Compound: substance containing 2 or more elements chemically joined together
e. Mixtures: contains 2 or more substances not chemically joined together. e.g. seawater is made up of water and NaCl (salt); oxygen in air varies Compounds vs MixturesIonic bond
Deducing formula ionic compounds
We have to balance the charges to make a stable bond. Ions present: Al3+ SO42- Al3+ SO42- SO42- Total change: 6+ 6- Therefore, the formula is Al2(SO4)3 1. The symbol of metal ion should always be first, e.g. NaCl 2. Polyatomic ion should be placed in brackets, e.g. Fe(NO3)2 Structure and Properties of ionic bondStructure
Covalent bond
Structure and Properties of covalent bondStructure a. Giant Covalent Bond
Properties
Metallic bond
Structure and Properties of metallic bond
Simple Molecular Substances
Noble gases- Noble Gases like helium and argon are unreactive.- do not form chemical bonds with other atoms as they have a stable electronic configuration. - Atoms of other elements form chemical bonds so that they attain the electronic configuration of a noble gas Drawing StructuresMCQ Questions1. Which ion has the most shells that contain electrons?a. Al3+ b. Be2+ c. N3- d. S2- 2. Which substance contains covalent bonds but also conducts electricity? a. brass b. graphite c. iodine d. steel 3. Which electron arrangement is that of a metallic element? a. 2, 1 b. 2, 4 c. 2, 5 d. 2, 7 4. Which molecules have the same number of protons? a. O2 and N2 b. Cl2 and Br2 c. CO2 and SO2 d. CH4 and NH3 5. Metals have positive ions in a 'sea of electrons'. Which metal atom provides most electrons for the sea? a. aluminium b. magnesium c. sodium d. zinc 6. Which substance does not have a macromolecular structure? a. diamond b. graphite c. silicon dioxide d. sodium chloride 7. Which atom has the same electronic configuration as the strontium ion? a. calcium b. krypton c. rubidium d. selenium 8. Element X has an electronic structure 2.8.8.1. Element Y has an electronic structure 2.8.6. What is made when X and Y react? Type of compound Formula a. covalent X2Y b. covalent XY2 c. ionic X2Y d. ionic XY2 9. What is the formula of uranium(VI) oxide? a. U6O b. U2O3 c. UO3 d. UO6 10. Graphite is used to make a. glass b. cutting tools c. electrical wiring d. electrodes 11. Which compound has both ionic and covalent bonds? a. ammonium chloride b. carbon dioxide c. ethy ethanoate d. sodium chloride 12. Elements X and Y react to form an ionic compound of formula XY. What could be the proton (atomic) numbers of X and Y?
13. An atom of an element contains 17 protons, 18 neutrons and 17 electrons. What is the atomic structure of another isotope of this element?
14. Which of the following has the highest electrical conductivity? a. aqueous sugar solution b. solid graphite c. solid sodium chloride d. gaseous carbon dioxide 15. Which of the following ions has the same number of electrons as a krypton atom, atomic number 36? a. chlorine b. rubidium c. sodium d. xenon 16. Which of the following is a compound? a. air b. carbon c. oxygen d. steam 17. In which set do the three particles each have the same total number of electrons?
18. An ion X+ has 23 nucleons and 10 electrons. What does the nucleus of the ion X+ contain?
19. The table shows information about particles X and Y.
Which statement is correct for both X and Y? a. they are atoms of metals b. they are atoms of noble gases c. they are isotopes of the same element d. they are negative ions 20. Which substance could be sodium chloride?
21. Chemical bonding involves the rearrangement of a. molecules b. atoms c. electrons d. ions 22. Solid carbon dioxide (dry ice) is used as a refrigerating agent because it readily changes directly from the solid state into the gaseous state at a low temperature. Based on the above information, what is the main intermolecular bonding in CO2 (s) likely to be? a. covalent bonding b. ionic bonding c. hydrogen bonding d. Van der Waals forces 23. Which of the following does not contain covalent bonds? a. graphite b. gold c. ice d. diamond 24. Which atom has the same electronic configuration as the strontium ion? a. calcium b. krypton c. rubidium d. selenium 25. How does a magnesium atom form a bond with an oxygen atom? a. by giving one pair of electrons to the oxygen atom b. by sharing one pair of electrons, provided by the magnesium atom c. by sharing two pairs of electrons, both pairs provided by the oxygen atom d. by sharing two pairs of electrons, each atom donating one pair of electrons 26. In which of the following pairs do the elements form a compound by sharing electrons? a. carbon and chlorine b. lithium and iodine c. neon and oxygen d. potassium and bromine 27. Which substance does not have a macromolecular structure? a. diamond b. graphite c. silicon dioxide d. sodium chloride 28. Which substance has the highest melting point? a. diamond b. lead(II) bromide c. methane d. water 29. Substance X has a melting point higher than 500ºC. It is insoluble both in water and in organic solvents. It conducts electricity both when solid and when molten. What could X be? a. copper b. magnesium oxide c. poly(ethene) d. silica 30. Which of the following describes the structure of diamond? a. a giant structure of atoms bonded covalently b. a regular arrangement of oppositely charged ions c. layers of rings of atoms d. positively charged ions surrounded by a sea of electrons MCQ Answers1. d2. b 3. a 4. d 5. a 6. d 7. b 8. c 9. c 10. d 11. a 12. d 13. a (isotopes of the same element have same number of protons but different number of neutrons) 14. b 15. b 16. d 17. b 18. b 19. d 20. d 21. c 22. d 23. b 24. b (both strontium ion and krypton have 36 electrons) 25. a (magnesium and oxygen undergo ionic bonding) 26. a 27. d (sodium chloride has a giant ionic structure made up of a lattice of positive and negative ions held tightly together by strong electrostatic forces of attraction - ionic bonds) 28. a (a lot of energy is needed to break the extremely strong C-C covalent bonds in diamond) 29. a 30. a Structured Question Worked Solutions1. Uranium-235 and uranium-238 are two isotopes of uranium. The table below shows the numbers of the particles in one atom of uranium-235
a. suggest a reason why this is known as uranium-235 b. In the table below, give the numbers of particles found in an atom of uranium-238
c. Uranium-235 is radioactive and is used in the manufacture of nuclear weapons. Give one other use of uranium-235 Solutions a. mass number = 143 + 92 = 235 b.
c. as a nuclear fuel in the production of nuclear energy 2. Fluorine can form either covalent or ionic bonds. a. Draw a dot-and-cross diagram to show the bonding in i. sodium fluoride, NaF ii. fluorine, F2 Your diagrams must show all electrons. b. Explain why sodium fluoride has a higher melting point than fluorine Solutions ai. aii. b. In NaF, the ionic bonds are very strong. In F2, the forces of attraction between F2 molecules are very weak. A lot of energy is required to break the strong ionic bonds. Hence, NaF has a higher melting point than F2. 3. Use the information in the table below to answer the following questions
ai. Name two metals from the table aii. How can you tell from the table that the substances you have chosen in (i) are metals? b. How can you tell from the table that wax is a mixture? ci. Name a compound from the table cii. Explain the meaning of the word compound d. Describe how the arrangement and movement of particles in aluminium change as the temperature rises from 659oC to 661oC e. Suggest how you could separate a mixture of sulphur and sodium chloride to produce a sample of each Solution ai. tungsten and aluminium aii. They conduct electricity when solid b. Wax melts over a range of temperatures ci. sodium chloride cii. a compound contains 2 or more elements chemically bonded together. The ratio of each element is fixed. d. At 659oC, the particles are vibrating vigorously about their fixed positions. At 660oC, Al starts to melt and the particles break free from each other and begin to move about in aggregates. e. Dissolve the mixture in water and filter. Sulphur remains as residue while NaCl is collected as filtrate. NaCl can then be obtained by crystallization. 4. The table shows the atomic structure of six particles, represented by the letters L to Q. The particles are atoms or ions. The letters are not the symbols of the elements.
Use the letters L to Q to answer the following questions. a. Which 2 particles are ions? b. Which particle is a atom of a noble gas? c. Which 2 particles are an atom and an ion of the same element? d. Which 2 particles are isotopes of the same element? e. Which particle has the highest atomic mass? Solutions a. O and Q (because O is an ion with a 2+ charge while Q is an ion with a 3+ charge) b. M c. N and O (N and O have the same number of protons but different number of electrons d. L and P have the same number of protons but different number of neutrons e. Q. (13 + 14 =27) 5. Sodium is stored under oil because it rapidly oxidises to form sodium oxide, Na2O. Draw a dot-and-cross diagram to show the bonding in sodium oxide. (Only need to show outer shell electrons) Solution |
Chemistry >