BLM 1-1, Interpreting an MSDS/Skill Builder

CHAPTER 1

ANSWER KEY

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BLM 1-1, Interpreting an MSDS/Skill Builder

Goal: Students demonstrate their understanding of the information on a chemical label and a Material Safety Data Sheet (MSDS) .

Answers

1. (a) The name of the substance is cupric sulfate pentahydrate. The chemical formula is CuSO4·5H2O.

(b) The substance is potentially toxic either by absorption or by inhalation.

(c) To avoid exposure, students should wear safety glasses, an apron, and gloves. Although not stated, proper ventilation is essential. The dust should not be inhaled.

(d) Excess amounts of this chemical should be deposited in a labelled waste container.

(e) The teacher should be informed immediately. The teacher should immediately contact poison control or medical personnel to find out how to proceed. It is likely that vomiting will need to be induced.

2. Note: For this question, search the Internet to find MSDS sheets to give your students. Use a search engine to search for an MSDS for any chemical by typing in “MSDS” and the name of the chemical. You may wish to provide all students with copies of the same MSDS, or provide a variety of MSDS sheets. Answers are given below for an MSDS for strontium nitrate, Sr(NO3)2.

(a) The name of the substance is strontium nitrate. The chemical formula is Sr(NO3)2.

(b) The substance is slightly dangerous to your health. It may cause irritation of the skin, eyes, lungs, or gastrointestinal tract. Long-term exposure may result in liver, kidney, bone, blood, and nerve damage.

(c) Inhalation of the dust from the chemical should be avoided. Students should wear gloves, goggles, and aprons. The substance must not be mixed with a reducing agent, because this could cause a fire.

(d) In the event of a fire, firefighters should wear full protective clothing and a self-contained breathing apparatus.

(e) All sources of ignition should be removed and proper ventilation should be initiated. Cleaning precautions should be taken to minimize or avoid dispersion of dust into the air. Waste should be sent to an appropriate hazardous waste facility.

(f) The material should be stored in a cool, dry location.

BLM 1-2, Anatomy of an Atom/ Information Handout

Answers

not applicable

BLM 1-3, Periodic Table/Information Handout

Answers

not applicable

BLM 1-4, Periodic Table Scavenger Hunt/Skill Builder

Goal: Students demonstrate their understanding of the periodic table.

Answers

1. Answers are in boldface.

The element called chromium has an atomic number of 24. Its symbol is Cr. When an atom of this element has a mass number of 52, the atom contains 24 protons and 28 neutrons. The most common ion charge of this element is 3+.

2. (a) niobium, Nb

(b) bromine, Br

(d) technetium, Tc

(e) tellurium, Te

(f) beryllium, Be

(g) xenon, Xe

CHAPTER 1

ANSWER KEY

3. Answers are in boldface.

Name of element / Symbol of isotope / Atomic number / Atomic mass / Number of protons / Number of electrons / Number of neutrons
silicon / / 14 / 28 / 14 / 14 / 14
oxygen / / 8 / 16 / 8 / 8 / 8
chromium / / 24 / 52 / 24 / 24 / 28
sodium / / 11 / 23 / 11 / 11 / 12
aluminium / / 13 / 27 / 13 / 13 / 14
potassium / / 19 / 39 / 19 / 19 / 20
beryllium / / 4 / 9 / 4 / 4 / 5

5. (a) neon –20

(b) sodium –23

6. (a)

(c)

7. The bold “staircase” line in the periodic table separates the metals (left) from the non-metals (right).

8. Halogens may be gases, liquids, or solids at room temperature and pressure. Alkali metals are all shiny solids. Alkali metal atoms have one valence electron. Halogen atoms have seven valence electrons. Alkali metals are found in group 1 of the periodic table. Halogens are found in group 17 of the periodic table.

CHAPTER 1

ANSWER KEY

BLM 1-5, Electron Dot Diagrams/Skill Builder

Goal: Students demonstrate their understanding of energy levels and practise drawing electron dot diagrams.

Answers

1. Answers are in bold face.

Name of element / Period number / Group number / Number of energy levels / Number of valence electrons
hydrogen / 1 / 1 / 1 / 1
aluminium / 3 / 13 / 3 / 3
oxygen / 2 / 16 / 2 / 6
strontium / 5 / 2 / 5 / 2
silicon / 3 / 14 / 3 / 4
barium / 6 / 2 / 6 / 2

Name of element

Energy level diagram

/ Electron dot diagram
carbon / /
oxygen / /
lithium / /
chlorine / /

CHAPTER 1

ANSWER KEY

Name of element

Energy level diagram

/ Electron dot diagram
magnesium / /
phosphorus / /

BLM 1-6, Drawing Electron Dot Diagrams/ Science Inquiry

Goal: Students practise drawing electron dot diagrams.

Answers

Answers to the questions for Find Out Activity: Drawing Electron Dot Diagrams are provided in the SCIENCEFOCUS 10 Teacher’s Resource.

BLM 1-7, Isotopes and Ions/ Reinforcement

Goal: Students demonstrate their understanding of isotopes and practise identifying and naming ions.

Answers

1. Answers are in boldface in the table below.

Name of ion

/ Symbol / Number of protons / Number of electrons / Net charge
lithium ion / Li+ / 3 / 2 / 1+
potassium ion / K+ / 19 / 18 / 1+
magnesium ion / Mg2+ / 12 / 10 / 2+
chloride ion / Cl– / 17 / 18 / 1–
fluoride ion / F– / 9 / 10 / 1–
oxide ion / O2– / 8 / 10 / 2–
iodide ion / I– / 53 / 54 / 1–
scandium ion / Sc3+ / 21 / 18 / 3+
sulfide ion / S2– / 16 / 18 / 2–
selenide ion / Se2– / 34 / 36 / 2–
nitride ion / N3– / 7 / 10 / 3–
aluminium ion / Al3+ / 13 / 10 / 3+
carbide ion / C4– / 6 / 10 / 4–
calcium ion / Ca2+ / 20 / 18 / 2+
phosphide ion / P3– / 15 / 18 / 3–

CHAPTER 1

ANSWER KEY

2. Answers are in boldface.

Name of isotope / Symbol / Mass number / Number of protons / Number of neutrons
hydrogen-3 (tritium) / H / 3 / 1 / 2
scandium-49 / / 49 / 21 / 28
cobalt-60 / / 60 / 27 / 33
nitrogen-15 / / 15 / 7 / 8
uranium-238 / / 238 / 92 / 146
iodine-129 / / 129 / 53 / 76
barium-135 / / 135 / 56 / 79
strontium-86 / / 86 / 38 / 48
oxygen-18 / / 18 / 8 / 10
carbon-14 / / 14 / 6 / 8

BLM 1-8, Ionic or Covalent: Track Those Electrons/Science Inquiry

Goal: Students use rings and diagrams to model the formation of ionic compounds and covalent compounds.

Answers

Answers to the questions for Investigation 1-A: Ionic or Covalent: Track Those Electrons are provided in the SCIENCEFOCUS 10 Teacher’s Resource.

BLM 1-9, Chapter 1 Test/Assessment

Goal: Students demonstrate their understanding of the information presented in Chapter 1.

Answers

1. T

2. T

3. F: Rutherford’s model of the atom was rejected because it could not explain emission spectra and the stability of atoms.

4. F: Bromine and mercury are the only elements in the periodic table that are liquids at room temperature.

5. F: All atoms of any one element must have the same number of protons.

6. (c)

7. (a)

8. (d)

9. (e)

10. (b)

11. law of conservation of mass

12. isotope

13. energy level

14. ion

15. covalent bond

16. (b)

17. (d)

18. (b)

19. (c)

20. (d)

21. (c)

22. (a)

23. (b)

24. (b)

25. (d)

26. Thomson’s model had electrons embedded within a sphere of positive charge. When Rutherford fired alpha particles at gold foil, most of the electrons were deflected only very slightly, while a very few bounced back. These results suggested that the atom was mostly empty space, with a dense, solid core. Thomson’s model did allow for these results, so it was rejected.

CHAPTER 1

ANSWER KEY

27. In an ionic bond, cations and anions are attracted strongly because they are oppositely charged. In a binary ionic compound, atoms of metal elements give up electrons to atoms of non-metal elements, in such a way that the atoms usually achieve a stable octet. In a covalent bond, atoms of non-metal elements share electrons, usually so that each atom achieves a stable octet.

28.

29. (a) The oxygen isotopes have the same number of electrons and the same number of protons. The number of neutrons does not affect reactivity. How elements form compounds is dictated primarily by the valence electrons.

(b)