A cluster of clear, cube-shaped salt crystals on a pale blue background

CHEMISTRY · IONIC BONDING

Salt From Poison

Follow along with your worksheet, one question at a time.

mrsajdak.com/salt

Photo: IvanSakhno, CC BY 4.0

BEFORE YOU START

What goes in, and what comes out

Sodium

A soft, silver metal. It catches fire in water.

Chlorine

A yellow-green gas. It is a poison.

Table salt

A white solid. You eat it every day.

Is salt just sodium and chlorine mixed together? Or is it something new?

Photos: Nefronus, CC0 · Larenmclane, CC BY-SA 4.0 · Stock Catalog, CC BY 2.0

BEFORE YOU START

Get set up

Open mrsajdak.com/salt on your device.

Write your name, the date and your period on the worksheet.

Find the four tabs at the top of the lab. Each tab goes with one part of the worksheet.

Start on Tab 1. Do not skip ahead.

The top of the lab page, showing the title and four tabs: The demo, One electron, Other salts, Test all three

Tab in the lab	Worksheet	Questions
1. The demo	Part 1	1 to 5
2. One electron	Part 2	6 to 9
3. Other salts	Part 3	10 and 11
4. Test all three	Part 4 and Wrap it up	12 to 14

Screenshot: mrsajdak.com/salt

A tall orange fireball and a spray of sparks where water was poured on sodium metal outdoors

TAB 1 · QUESTIONS 1 TO 5

Part 1. The demo

Sodium and chlorine react to make salt. The reaction gives off heat and a yellow flame.

Chlorine gas is too dangerous for a classroom. So you will run it in the lab, in a sealed flask on a balance.

Photo: Ajhalls, public domain

PART 1 · TAB 1

Run the demo

Drag the Sodium on the sand slider. It sets the grams of sodium.

Press Add a drop of water to watch. Or press Skip to the end.

Read the Before and After columns.

Press New flask to go again.

Your runs keeps one row for each amount.

The demo box in the lab: a slider for sodium on the sand, a note that the flask holds 2.95 g of chlorine, and buttons for Add a drop of water and Skip to the end

The sealed flask on a balance while the sodium burns with a yellow flame, beside bars that show the mass inside the flask

The slider goes from 0.1 g to 3.0 g.

The flask holds the same amount of chlorine every time.

Screenshots: mrsajdak.com/salt, Tab 1

PART 1 · QUESTION 1

Add up the masses

Set the sodium to 1.0 g. Run it.

Sodium used is sodium Before minus sodium After.

Find the chlorine used the same way.

Add the two. Then read the Salt row.

What do you notice?

The demo box after a run: a table with Before and After columns for sodium, chlorine, salt, the balance and the heat given off

Example

Chlorine before: 5.00 g.

Chlorine after: 3.20 g.

5.00 − 3.20 = 1.80

So 1.80 g of chlorine was used.

These are not your numbers. Use your own.

Screenshot: mrsajdak.com/salt, Tab 1

PART 1 · QUESTION 2

Six runs, one table

Run six amounts of sodium: 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 g.

After each run, copy Heat given off from the After column. It is not in Your runs.

Then press New flask.

At the end, copy Salt made and Left over from Your runs.

The Your runs box in the lab: three rows showing sodium in, salt made and what was left over

“Left over” is what is still in the flask after the flame goes out. Write what it is and how much.

These three rows are 0.3, 0.7 and 1.2 g. They are not in your table.

Screenshot: mrsajdak.com/salt, Tab 1

PART 1 · QUESTIONS 3 AND 4

When the salt stops growing

QUESTION 3

Limiting reactant

Compare 0.5 g and 1.0 g in your table. Then compare 2.0 g and 3.0 g.

The reactant that runs out first is the limiting reactant. The sentence under the After column tells you what ran out.

QUESTION 4

Find the switch

Move the slider in 0.1 g steps. Run each one.

Watch Left over. Find the two amounts where it changes from chlorine to sodium.

The lab graph of salt made against sodium added, with three dots joined by a rising line

Each run adds a dot. Look at the shape of the line once all six dots are on it.

This graph has only three small runs on it.

Screenshot: mrsajdak.com/salt, Tab 1

PART 1 · QUESTION 5

Watch the balance

Before

Run 1.0 g again. Read the Balance row in the Before column.

After

Read the Balance row in the After column.

Why?

A green gas and a silver metal turned into a white solid. The flask is sealed. What does that tell you about the atoms inside?

The flask after the reaction, coated with white salt, sitting on a balance, beside Before and After bars for the mass inside the flask

The green number under the flask is the balance. The bars show the mass inside the flask.

Screenshot: mrsajdak.com/salt, Tab 1

A bright yellow-orange flame on a lab burner, made by holding salt on a wooden stick in the flame

TAB 2 · QUESTIONS 6 TO 9

Part 2. One electron

Zoom in on one sodium atom and one chlorine atom inside that flame.

One electron moves. That makes two ions: atoms with a charge.

Photo: S k y r, CC BY 4.0

PART 2 · TAB 2

Move one electron

Click sodium’s gold electron. Or press 1. Move the electron.

Watch both atoms change size.

Press 2. Let them meet.

Press 3. Zoom out to the crystal.

Start over puts the electron back.

The One electron box in the lab, with buttons for Move the electron, Let them meet, Zoom out to the crystal and Start over

A sodium atom and a chlorine atom drawn as rings of electrons, with one gold electron on the outside of the sodium atom

Blue dots are electrons. The gold one is the one that moves.

The number in the middle of each atom is its protons.

Screenshots: mrsajdak.com/salt, Tab 2

PART 2 · QUESTION 6

Four particles, one table

Column	Where to look
Electrons by shell	The Atoms and ions box
Protons	Under each atom in the picture
Electrons	Under each atom in the picture
Charge	The Atoms and ions box
Radius (pm)	The Atoms and ions box

The top of the Atoms and ions box in the lab, with columns for particle, electrons by shell, charge and radius

Fill in the two atom rows first.

Then move the electron. The two ion rows show up.

A pm is a picometre. That is a trillionth of a metre.

Screenshot: mrsajdak.com/salt, Tab 2

PART 2 · QUESTIONS 7 AND 8

Why only one electron?

QUESTION 7

Same as

Match the noble gas

Move the electron. Read the last line under each ion in the picture.

It names a noble gas with the same electrons.

QUESTION 7

Smaller

Why did Na⁺ shrink?

Compare Electrons by shell for Na and Na⁺ in your table.

What happened to the outer shell?

QUESTION 8

2nd

Try for a second one

Press Try to pull a second electron off Na⁺.

Write both energies. Divide the second by the first.

PART 2 · QUESTION 9

Where the heat comes from

Press 2. Let them meet. Now every bar shows.

Orange bars cost energy. Find the biggest one.

Blue-green bars give energy back. Find the biggest one.

Read the Net bar. It is for 58.44 g of salt.

Check it against Tab 1. Show your math.

The lab bar graph called Where the heat comes from, with two orange bars filled in and question marks where the other bars will go

Example

40 ÷ 10 = 4
4 × 50 = 200

If 10 g gives off 50 kJ, then 40 g gives off 200 kJ. These are not your numbers.

Screenshot: mrsajdak.com/salt, Tab 2

A large cluster of dark purple, cube-shaped fluorite crystals

TAB 3 · QUESTIONS 10 AND 11

Part 3. Other salts

Table salt is one salt. There are many more.

Each one is made the same way. A metal gives away electrons. A nonmetal takes them.

Photo: James St. John, CC BY 2.0

PART 3 · TAB 3

Build a salt

Pick a Metal and a Nonmetal.

Click a purple electron. Then click a nonmetal atom with an open spot.

Stuck? Read the red message. Press + to add an atom.

Keep going until every metal atom is empty and every nonmetal has 8.

The formula shows up when you are done.

The Build a salt box in the lab: buttons to pick a metal and a nonmetal, plus and minus buttons for the number of atoms, and a red message that says to add another metal atom

One lithium atom that has given away its electron and one nitrogen atom that still has open spots

Dashed circles are open spots.

Adding an atom puts all the electrons back. You can use up to 3 atoms of each.

Put the electrons back lets you try again.

Screenshots: mrsajdak.com/salt, Tab 3

PART 3 · QUESTIONS 10 AND 11

Six salts, then a pattern

Column	Where to look
Outer electrons	The Outer electrons box
Atoms needed	The two counters, once the salt is done
Formula	The box that shows up when you finish
Ion charges	Salts you made, in the Ions column

A formula uses the smallest whole numbers. The lab tells you if you used more atoms than you need.

The Salts you made box in the lab, with one row showing a formula, a name and the ions

QUESTION 11

Find the pattern

Compare each metal’s outer electrons with its charge. Do the same for the nonmetals.

Then predict calcium + chlorine. Do not use the lab.

Screenshot: mrsajdak.com/salt, Tab 3

A hand holding a large, clear, cube-shaped crystal of salt

TAB 4 · QUESTIONS 12 AND 13

Part 4. Test all three

Sodium, chlorine and salt share the same atoms.

Do they act the same? Run five tests on each one and find out.

Photo: IvanSakhno, CC BY 4.0

PART 4 · QUESTION 12

Run every test

Pick a Substance: Sodium, Chlorine or Table salt.

Press a test. Wait for it to finish.

Read the sentence under the buttons.

Do all five tests. Then pick the next substance.

Check Your results. It should say 15 of 15 tests done.

The Test all three box in the lab: buttons for Sodium, Chlorine and Table salt, and five test buttons: Look at it, Melting point, Conducts as a solid, Conducts when melted, Drop it in water

The Your results box in the lab: a grid of five tests for sodium, chlorine and salt, with question marks in every space

A ? means you have not run that test yet.

The sentence tells you more than the grid does.

Screenshots: mrsajdak.com/salt, Tab 4

PART 4 · QUESTION 13

Why does melted salt light the bulb?

Look back

Go to Tab 2. Press the buttons until you see the crystal.

Solid

Look at the ions in the crystal. Can they move around?

Melted

What changes for the ions when the crystal melts?

Electricity needs charges that can move. Use the word ions in your answer.

The salt crystal from Tab 2: a block of small purple sodium ions and large green chloride ions joined in a cube pattern

The crystal from Tab 2. Purple is Na⁺. Green is Cl⁻.

Screenshot: mrsajdak.com/salt, Tab 2

WRAP IT UP · QUESTION 14

Is salt a new substance?

The claim

“Salt is a new substance. It is not just sodium and chlorine mixed together.”

Evidence 1

Pick a number or a result from one tab. Your Question 12 table is a good place to look.

Evidence 2

Pick one from a different tab. Try your Question 2 or Question 6 table.

Reasoning

Say what happened to the atoms and their electrons.

One grain of table salt seen through an electron microscope. It is a cube with rounded edges.

One grain of table salt under an electron microscope. It is a tiny cube.

Photo: Chhe, public domain

White piles of sea salt beside shallow ponds, with a windmill behind them

LAST CHECK

Before you hand it in

Name, date and period are on top.

All four tables are full.

Question 9 shows your math.

Question 14 has evidence from two tabs.

Photo: Matthias Süßen, CC BY 3.0