Unit 4 · Bonding · Checkpoint 5
⚗️ Electronegativity & Polarity
How hard atoms pull on electrons · polar vs. nonpolar bonds · polar vs. nonpolar molecules.
🪢 The big idea
Two atoms grab a rope. The stronger atom pulls harder.
That is electronegativityHow hard an atom pulls on shared electrons in a bond. Higher number = stronger pull.How hard an atom pulls. Big number = strong pull.. Some atoms pull electrons hard. Some pull soft. The number tells you who pulls hardest.
electronegativityWhy does this matter?
- Salt dissolves in water but oil does not.
- Soap cleans grease.
- Water sticks to itself in beads but mercury does not.
Every one of these is electronegativity at work.
📔 Take notes
📔 How to use this — first time? Open me.
This is a notes scaffold. A scaffold is training wheels — it shows you what to write down. Once you do this for a few checkpoints, you'll know how to take notes on your own.
Today's job: two columns.
- Left column (already filled in): every key word from this checkpoint.
- Right column (your job): write what each word means, in your own words. Not the dictionary. Your words. Like you're explaining it to a friend.
Why your own words? If you can rewrite a definition in your own words, you actually understand it. If you can only copy the textbook, you don't (yet). That's what we're building toward.
How long should each definition be? One short sentence. If you need two, that's fine. If you write a whole paragraph, you're trying too hard — shorter is better.
Stuck on a word? Hover the underlined words in the reading below — the tooltip gives you the dictionary definition. Read it, close the tooltip, write your own version without looking.
| Word | What it means (your words) |
|---|---|
| electronegativity | |
| periodic-trend | |
| nonpolar-bond | |
| polar-bond | |
| partial-charge | |
| dipole | |
| asymmetrical | |
| solvent | |
| solute | |
| universal-solvent | |
| dissolve | |
| symmetrical | |
| polar-molecule |
Your big takeaway
Finish this sentence in your own words:
If a friend asked "what is this checkpoint about?", I would say:
🎬 Videos — Watch in Your Language First
🇺🇸 English Videos
🎬 Main — Watch This First:
- Electronegativity Trends — Amoeba Sisters — Clear animations showing how EN changes across the periodic table.
- Polar vs Nonpolar Molecules — Amoeba Sisters — Simple explanation of why shape decides polarity.
🔁 More Practice:
- Electronegativity — Tyler DeWitt — Very simple language. Good tug-of-war explanation.
- Polar and Nonpolar Molecules — The Organic Chemistry Tutor — Lots of examples. Step by step.
- Electronegativity and Bond Polarity — Professor Dave Explains — Clear visuals and comparisons.
🪜 Simple & Visual:
- What is Electronegativity? — It's AumSum Time — Cartoon style. Very easy to follow.
- Polar and Nonpolar Explained — It's AumSum Time — Cartoon style. Great for visual learners.
- Electronegativity — FuseSchool — Short, clear, good diagrams.
🇲🇽 Videos en Español
Video principal:
- Electronegatividad — Ameba Proteus — Explica la electronegatividad con animaciones claras.
- Moléculas polares y no polares — Quimitube — Buenos ejemplos visuales.
Más práctica:
- Electronegativity — Amoeba Sisters — Activa subtítulos: ⚙️ → Subtítulos → Traducción automática → Español.
Consejo: Mira el video en español primero, luego mira el video en inglés.
🇧🇷 Vídeos em Português
Vídeo principal:
- Eletronegatividade — Me Salva! — Aula rápida e direta.
- Polaridade das Moléculas — Descomplica — Explicação clara com exemplos do dia a dia.
Dica: Assista o vídeo em português primeiro, depois assista o vídeo em inglês.
🇫🇷 Vidéos en Français
Vidéo principale:
- Électronégativité et polarité — Khan Academy — Explication claire avec schémas.
Vidéo anglaise avec sous-titres:
- Electronegativity — Amoeba Sisters — Activez : ⚙️ → Sous-titres → Traduire automatiquement → Français.
Conseil: Regardez la vidéo en français d'abord, puis regardez la vidéo en anglais.
🇻🇳 Tài liệu Tiếng Việt
Video chính:
- Độ âm điện — Hóa học vui — Giải thích đơn giản bằng tiếng Việt.
Video tiếng Anh có phụ đề:
- Electronegativity — Amoeba Sisters — Bật phụ đề tự động (CC) → Settings → Auto-translate → Tiếng Việt.
Mẹo: Xem video tiếng Việt trước, sau đó xem video tiếng Anh.
🇸🇦 موارد باللغة العربية
الفيديو الرئيسي:
- الكهروسالبية — التعليم الممتع — شرح واضح مع رسوم متحركة.
فيديو إنجليزي مع ترجمة:
- Electronegativity — Amoeba Sisters — اضغط ⚙️ → الترجمة → الترجمة التلقائية → العربية.
نصيحة: شاهد الفيديو بالعربية أولاً، ثم شاهد الفيديو بالإنجليزية.
🇭🇹 Resous an Kreyòl Ayisyen
⚠️ Onèt: Pa gen anpil videyo syans an Kreyòl sou YouTube. Men sa nou jwenn ki pi bon pou ou:
Videyo an Fransè (anpil Ayisyen pale Fransè tou):
- Électronégativité — Khan Academy — Eksplikasyon klè ak desen.
Videyo anglè senp ak anpil vizyèl:
- What is Electronegativity? — It's AumSum Time — Anglè senp, desen animé. Trè fasil konprann.
- Polar and Nonpolar — It's AumSum Time — Anglè senp, desen animé. Trè fasil konprann.
Kijan pou mete soutit an Fransè (pi pre Kreyòl):
- Ouvri videyo YouTube a.
- Peze ⚙️ (ti wou angranaj la) anba videyo a.
- Peze Subtitles/CC.
- Peze Auto-translate.
- Chwazi Français.
📖 Reading: Why Some Molecules Have Two Sides
Part 1: What Is Electronegativity?
Imagine a tug of war. Two people grab a rope and pull. The stronger person pulls the rope closer to them.
In a chemical bond, two atoms share electrons. But they do not always share equally. Some atoms pull harder on the shared electrons. How hard an atom pulls is called its electronegativityHow hard an atom pulls on shared electrons in a bond. Higher number = stronger pull.How hard an atom pulls. Big number = strong pull. (EN).
Fluorine (F) has the highest EN of all elements (4.0). It pulls the hardest. Francium (bottom left corner) has the lowest. It barely pulls at all.
🔑 Key Idea: Electronegativity = how hard an atom pulls on shared electrons. Higher EN = stronger pull.
Part 2: EN on the Periodic Table
Electronegativity follows a pattern — a periodic-trendA pattern in element properties (like electronegativity, atomic size, or reactivity) that shows up as you move across or down the periodic table.A pattern on the periodic table. — on the periodic table:
periodic-trend- Across a period (→): EN increases. Atoms get smaller and pull harder.
- Down a group (↓): EN decreases. Atoms get bigger, and the outer electrons are far from the nucleus.
So the highest EN atoms are in the top right (F, O, N, Cl). The lowest are in the bottom left (Cs, Fr).
Noble gases do not have EN values because they already have 8 electrons and do not bond with other atoms.
Use the Live ΔEN Explorer above to see this pattern as a heat map — bright colors are high EN, faded colors are low EN.
💡 Think About It: Between sodium (Na) and chlorine (Cl), which pulls electrons harder? (Na / Cl). How do you know? Because Cl is further to the (right / left) on the periodic table.
Part 3: Three Types of Bonds
The electronegativity difference (ΔEN) between two atoms tells you what kind of bond they make:
- ΔEN = 0 to 0.4 → nonpolar-bondA bond where electrons are shared equally between two atoms.Two atoms share electrons the same. (covalent). The atoms share electrons equally. The rope stays in the middle. Example: H–H in H₂.
- ΔEN = 0.5 to 1.7 → polar-bondA bond where electrons are shared unequally — one atom pulls them closer than the other.Two atoms share electrons. One atom pulls more. (covalent). The atoms share unequally. The stronger atom pulls the electrons closer. Example: O–H in water.
- ΔEN = 1.8 or more → Ionic. One atom pulls so hard it takes the electrons completely. Example: Na–Cl in table salt.
nonpolar-bond
polar-bondThese are not three separate things — they are a spectrum. As the difference gets bigger, the sharing gets more unequal, until eventually one atom takes the electrons completely.
🔑 Key Idea: Small ΔEN = equal sharing (nonpolar). Medium ΔEN = unequal sharing (polar). Big ΔEN = transfer (ionic).
Part 4: What Makes a Polar Bond
In a polar bond, the electrons spend more time near the atom with higher EN. That atom becomes slightly negative (δ−). The other atom becomes slightly positive (δ+). These small charges are called partial-chargeA small, partial positive (δ+) or negative (δ-) charge on an atom in a polar bond — not a full charge like in an ion.A little bit + or a little bit −. Not a full charge.s.
partial-chargeFor example: in an O–H bond, oxygen has EN = 3.5 and hydrogen has EN = 2.1. The ΔEN is 1.4, so the bond is polar covalent. Oxygen pulls the electrons closer. Oxygen is δ− and hydrogen is δ+. The pair is now a dipoleA separation of positive and negative charge across a bond or molecule.A + side and a − side. Like a magnet. — it has a positive end and a negative end.
dipoleThink of it like a seesaw. If one person is heavier, the seesaw tips toward them. In a polar bond, the electrons "tip" toward the atom with higher EN.
Part 5: Polar Bonds vs. Polar Molecules
Here is the tricky part. A molecule can have polar bonds but still be nonpolar!
Think about it like this: Two people pull a wagon in opposite directions with equal force. The wagon does not move. The pulls cancel out.
In CO₂, the C–O bonds are polar (O pulls harder than C). But CO₂ is linear — the two polar bonds point in opposite directions and cancel. The molecule is nonpolar.
In H₂O, the O–H bonds are also polar. But water is bent — the two polar bonds point in the same general direction. They do NOT cancel. The molecule is polar.
The rule: To be a polar molecule, you need polar bonds AND an asymmetricalNOT the same on all sides. In chemistry: a molecule shape where the polar bonds do NOT cancel out, making the molecule polar.Not the same on both sides. Uneven shape. shape.
asymmetricalUse the Polar Math widget above to see this with arrows. CO₂ arrows cancel; H₂O arrows do not.
💡 Think About It: CH₄ (methane) has 4 C–H bonds. These bonds are slightly polar (ΔEN = 0.4). But CH₄ has a tetrahedral shape — all 4 bonds cancel. Is CH₄ polar or nonpolar? (polar / nonpolar).
Part 6: Like Dissolves Like
This is one of the most useful rules in chemistry: "Like dissolves like."
- Polar solventThe substance that does the dissolving — usually the liquid in which something is dissolved.The liquid that dissolves things. Water is one.s (like water) dissolve polar soluteThe substance that gets dissolved — usually a solid that disappears into a liquid.The thing that gets dissolved. Salt or sugar.s (like salt, sugar).
- Nonpolar solvents (like oil, gasoline) dissolve nonpolar solutes (like grease, wax).
- Polar and nonpolar do NOT mix well. That is why oil and water separate!
solvent
soluteWater is called the universal-solventA nickname for water, because its polar shape lets it dissolve more substances than any other liquid.Water — it dissolves more things than any other liquid. because its bent, polar shape lets it dissolveTo break apart and mix evenly into a liquid until you can no longer see the individual pieces.To mix and disappear into a liquid. more substances than any other liquid. The δ+ end (hydrogen) attracts negative ions, and the δ− end (oxygen) attracts positive ions. Water literally pulls ionic compounds apart.
universal-solvent
dissolveUse the Like-Dissolves-Like Sandbox above to test this — drop salt, oil, sugar, and dish soap into water vs oil and watch what happens.
Part 7: Polarity in Real Life
Polarity explains so many everyday things:
- Dish soap has a polar end AND a nonpolar end. The nonpolar end grabs grease. The polar end dissolves in water. Soap is a bridge between polar and nonpolar!
- Oil and vinegar in salad dressing separate because oil is nonpolar and vinegar (mostly water) is polar.
- Rubbing alcohol cleans grease because it has both polar and nonpolar parts.
- Cell membranes are made of phospholipids — molecules with a polar head (loves water) and nonpolar tails (hides from water). This double nature creates the barrier around every cell in your body.
🔑 Key Idea: Polarity affects how molecules interact. "Like dissolves like." Shape determines if a molecule is polar or nonpolar.
Part 8: What's Coming Next
Now you understand electronegativity, polar vs. nonpolar bonds, and how shape determines molecular polarity. Next, you will learn about naming compounds — the rules for giving ionic and covalent compounds their official names.
You will learn prefixes like mono-, di-, tri-, and tetra- for covalent compounds. You will learn how to name ionic compounds using the metal name and the -ide ending. And you will learn about polyatomic ions — groups of atoms that act like one ion.
🔑 Key Idea: Electronegativity tells you how hard atoms pull on electrons. The EN difference determines bond type. The molecule's shape determines if it is polar or nonpolar. Polarity determines what dissolves what.
👀 Look
1. Atoms pull on electrons.
Some atoms pull hard. Some pull soft.
F pulls hardest of all atoms.
2. Three kinds of bonds.
3. A polar bond has two sides.
One side is +. One side is −.
4. Polar molecule = uneven shape.
Water (H₂O) is uneven → polar.
CO₂ is even → nonpolar.
5. Like dissolves like.
Polar dissolves polar. (Salt + water ✓)
Nonpolar dissolves nonpolar. (Oil + oil ✓)
Polar + nonpolar = NO mix. (Oil + water ✗)
6. Soap is special.
Soap has two ends. One loves water. One loves grease.
That is why soap cleans.
📖 Vocabulary — All Languages
Hover any underlined word in the reading below for a quick definition. The full table is here for reference.
| English | Español | Português | Français | Tiếng Việt | العربية | Kreyòl |
|---|---|---|---|---|---|---|
| electronegativity | electronegatividad | eletronegatividade | électronégativité | độ âm điện | كهروسالبية | elektwonegatitivite |
| polar bond | enlace polar | ligação polar | liaison polaire | liên kết phân cực | رابطة قطبية | lyezon polè |
| nonpolar bond | enlace no polar | ligação apolar | liaison non polaire | liên kết không phân cực | رابطة غير قطبية | lyezon pa polè |
| polar molecule | molécula polar | molécula polar | molécule polaire | phân tử phân cực | جزيء قطبي | molekil polè |
| nonpolar molecule | molécula no polar | molécula apolar | molécule non polaire | phân tử không phân cực | جزيء غير قطبي | molekil pa polè |
| symmetrical | simétrico | simétrico | symétrique | đối xứng | متماثل | simetrik |
| asymmetrical | asimétrico | assimétrico | asymétrique | bất đối xứng | غير متماثل | asimetrik |
| dipole | dipolo | dipolo | dipôle | lưỡng cực | ثنائي القطب | dipòl |
| partial charge (δ+/δ−) | carga parcial | carga parcial | charge partielle | điện tích riêng phần | شحنة جزئية | chaj pasyèl |
| solvent | solvente | solvente | solvant | dung môi | مذيب | solvan |
| solute | soluto | soluto | soluté | chất tan | مذاب | sòlit |
| dissolve | disolver | dissolver | dissoudre | hòa tan | يُذيب | fonn |
| periodic trend | tendencia periódica | tendência periódica | tendance périodique | xu hướng tuần hoàn | اتجاه دوري | tandans peryodik |
| universal solvent | solvente universal | solvente universal | solvant universel | dung môi vạn năng | مذيب عالمي | solvan inivèsèl |
🧪 Practice Tools
PhET: Molecule Polarity →
See how electronegativity creates polar bonds! Drag atoms to change the EN difference and watch the electron cloud shift. Build real molecules and see if they are polar or nonpolar.
Try this: Go to "Two Atoms" tab. Make atom A more electronegative. Watch the electrons move toward A! Then try "Three Atoms" and "Real Molecules."
MolView — 3D Molecule Viewer →
Search for any molecule and see its 3D shape. Compare the shapes of polar (H₂O, NH₃) and nonpolar (CO₂, CH₄) molecules. Spin the models to understand symmetry.
Try this: Search "water" and then "carbon dioxide." Compare the shapes. Which one looks symmetrical?
🌟 Try It Right Here
Three interactive tools, no sign-in, no installation. They work even if PhET or MolView is blocked at school.
📝 Notes Questions
🚨 HUGE HINT 🚨 — the checkpoint quiz is open notes (paper only, no phones). These questions prepare you for every version of the quiz. Answer all of them carefully — your answers become your best study tool.
Part A: Electronegativity — How Hard Atoms Pull
1. electronegativityHow hard an atom pulls on shared electrons in a bond. Higher number = stronger pull.How hard an atom pulls. Big number = strong pull. (EN) is how hard an atom pulls on shared electrons. Think about a tug of war. Two people pull on a rope. The stronger person pulls the rope closer to them. In a bond, the atom with higher EN pulls the electrons closer.
| Question | Answer (use the sentence frame) |
|---|---|
| What is electronegativity? | Electronegativity is how hard an atom on shared . |
| Which atom has the HIGHEST EN? | (F) has the highest EN (4.0). It pulls the hardest. |
| EN trend across a period (→)? | Going right across a period, EN . Atoms get at pulling electrons. |
| EN trend down a group (↓)? | Going down a group, EN . Atoms get at pulling electrons. |
| Why do noble gases not have EN values? | Noble gases already have valence electrons. They do not need to with other atoms. |
Word Bank: pulls / electrons / fluorine / increases / better / decreases / worse / 8 / bond
2. Rank these atoms from LOWEST to HIGHEST electronegativity. Use the periodic table trends.
| Atoms to rank | Order (lowest EN → highest EN) |
|---|---|
| Na, Cl, F | < < |
| C, N, O | < < |
| F, Cl, Br, I | < < < |
3. Think about it like this: Fluorine is the strongest player in tug of war. It is small and pulls VERY hard. Francium (bottom left of periodic table) is the weakest. It is big and does not pull well.
- Small atoms pull (harder / weaker) than big atoms.
- Atoms on the (right / left) of the periodic table pull harder.
- Atoms at the (top / bottom) of the periodic table pull harder.
Part B: Three Types of Bonds — The EN Difference Decides
4. The electronegativity difference (ΔEN) between two atoms tells you what type of bond they make. Fill in the table.
| Bond Type | ΔEN Range | What happens to electrons | Tug of war analogy |
|---|---|---|---|
| Nonpolar covalent | 0 to 0.4 | Electrons are shared | Both players are equal. The rope stays in the . |
| Polar covalent | 0.5 to 1.7 | Electrons are shared (pulled closer to one atom) | One player is . The rope moves toward them. |
| Ionic | 1.8 or more | Electrons are (taken completely) | One player is SO strong they the rope away. |
Word Bank: equally / middle / unequally / stronger / transferred / pull
5. Practice! Calculate the ΔEN and tell what type of bond each pair makes. Use the EN values given.
| Bond | EN values | ΔEN = ? | Bond type | Sharing is… |
|---|---|---|---|---|
| H–H | H = 2.1, H = 2.1 | 2.1 − 2.1 = | covalent | Equal |
| O–H | O = 3.5, H = 2.1 | 3.5 − 2.1 = | covalent | |
| Na–Cl | Na = 0.9, Cl = 3.0 | 3.0 − 0.9 = | Transferred! | |
| C–H | C = 2.5, H = 2.1 | 2.5 − 2.1 = | covalent | |
| C–O | C = 2.5, O = 3.5 | 3.5 − 2.5 = | covalent |
6. In a polar bond, electrons spend more time near the atom with (higher / lower) EN. This atom becomes slightly (δ−). The other atom becomes slightly (δ+). The symbols δ− and δ+ mean "a little negative" and "a little positive."
Part C: Polar vs. Nonpolar Molecules — Shape Decides
7. A molecule can have polar bonds but still be nonpolar! This happens when the shape is symmetricalThe same on all sides. In chemistry: a molecule shape where the polar bonds cancel each other out.The same on both sides. Even shape. and the polar bonds cancel each other out. Fill in the table.
symmetrical| Molecule | Shape | Polar bonds? | Symmetrical? | Polar or nonpolar molecule? |
|---|---|---|---|---|
| CO₂ | Linear | Yes (C–O is polar) | (pulls cancel) | — symmetrical shape cancels the polar bonds. |
| H₂O | Bent | Yes (O–H is polar) | (pulls do NOT cancel) | — bent shape means the pulls add up. |
| CH₄ | Tetrahedral | Slightly (C–H, ΔEN = 0.4) | (pulls cancel) | — symmetrical shape cancels. |
| NH₃ | Trigonal pyramidal | Yes (N–H is polar) | (lone pair breaks symmetry) | — lone pair makes it asymmetrical. |
| CCl₄ | Tetrahedral | Yes (C–Cl is polar) | (all 4 pulls cancel) | — symmetrical shape cancels. |
8. The rule is simple. To be a polar-moleculeA molecule with polar bonds AND an asymmetrical shape, so the pulls do not cancel out.A molecule with one + side and one − side. Like water., you need BOTH:
polar-molecule- Polar (an EN difference between atoms).
- An shape (so the pulls do NOT cancel out).
If the shape is symmetrical, the polar bonds cancel. The molecule is nonpolar even though the bonds are polar!
9. Think about it like this: Imagine 4 people playing tug of war in a circle. If all 4 pull equally, nobody moves — the pulls cancel. That is like CO₂ or CH₄. But if 2 people pull and 2 people just stand there (lone pairs), the team with people pulling wins — the molecule has a "direction." That is like H₂O or NH₃.
10. "Like dissolves like." This is one of the most important rules in chemistry. Fill in the blanks.
| Solute (thing being dissolved) | Solvent (thing doing the dissolving) | Will it dissolve? Why? |
|---|---|---|
| Salt (NaCl) — ionic/polar | Water (H₂O) — polar | — both are polar. Like dissolves like. |
| Oil — nonpolar | Water (H₂O) — polar | — they are not alike. Oil is and water is . |
| Oil — nonpolar | Gasoline — nonpolar | — both are nonpolar. Like dissolves like. |
| Sugar (C₆H₁₂O₆) — polar | Water (H₂O) — polar | — both are . Like dissolves like. |
11. Why can water dissolve so many things? Water is called the "universal-solventA nickname for water, because its polar shape lets it dissolve more substances than any other liquid.Water — it dissolves more things than any other liquid.."
Water is (polar / nonpolar). Its bent shape gives it a (δ+) end and a (δ−) end. The positive end attracts (negative / positive) ions and the negative end attracts (negative / positive) ions. This is why water can pull ions apart and dissolve salts.
12. Look at the PhET Molecule Polarity simulation. Build H₂O and CO₂. Compare what you see.
| Feature | H₂O | CO₂ |
|---|---|---|
| Shape | ||
| Polar bonds? | (yes / no) | (yes / no) |
| Do they cancel? | (yes / no) | (yes / no) |
| Polar molecule? | (yes / no) | (yes / no) |
13. Why does this matter in real life? Give one example where polarity affects something you see or do every day.
Example: ________________________________________________________________________________
✅ You finished the notes questions! Now watch the videos, study the vocabulary, use the interactive tools below, and read the passage to fill in any gaps.
👀 Look & Tap
1. Which atom pulls electrons hardest?
2. Which molecule is polar?
3. Which dissolves in water?
4. Which is symmetrical?
5. Which side is δ−?
📚 How to Prepare
🌉 Bridge Strategy: Use Your Home Language
English is the goal — your quiz and notes will be in English. But your home language is your bridge to understanding.
4 Steps:
- Watch a video in your home language to understand the concept.
- Watch the English video — you'll recognize the ideas.
- Read the English passage below — the vocabulary will make more sense.
- Practice explaining it in English using your notes.
📋 Quiz Format
- ✏️ PAPER ONLY — no phones, no Chromebooks.
- 📝 You CAN use your handwritten notes.
- 🔄 Retakes are available — this quiz checks understanding, not memorization.
🎯 What This Quiz Tests
This quiz tests your understanding, not memorization. You need to explain WHY and HOW:
- What electronegativityHow hard an atom pulls on shared electrons in a bond. Higher number = stronger pull.How hard an atom pulls. Big number = strong pull. means and how it changes across the periodic table.
- How to use the electronegativity difference to decide if a bond is nonpolar covalent, polar covalent, or ionic.
- What a polar-bondA bond where electrons are shared unequally — one atom pulls them closer than the other.Two atoms share electrons. One atom pulls more. looks like (unequal sharing of electrons).
- Why some molecules are polar and some are nonpolar (shape matters!).
- Why "like dissolves like" — polar dissolves polar, nonpolar dissolves nonpolar.
✅ You're Ready If You Can…
- Define electronegativity in simple words.
- Say which direction electronegativity increases on the periodic table.
- Tell if a bond is nonpolar covalent, polar covalent, or ionic using the EN difference.
- Explain what a polar bond is using the tug-of-war analogy.
- Look at a molecule and say if it is polar or nonpolar.
- Explain why water dissolves salt but oil does not.
- Draw arrows showing which atom pulls electrons harder in a polar bond.