Why is "Defining a covalent bond as 'when atoms share electrons' instead of 'a shared pair of electrons'" a common mistake in Formation of covalent bonds?

Why it happens: Students remember the idea of sharing but drop the mark-scheme phrase. How to avoid it: Write the exact phrase: **'a shared pair of electrons'**. The word **pair** is essential for the mark. Source: Edexcel Chemistry examiner reports — recurring error

Why is "Saying a covalent bond is 'the attraction between the two nuclei (atoms)'" a common mistake in Formation of covalent bonds?

Why it happens: Students know there is an attraction but point it at the wrong particles. How to avoid it: Both nuclei are **positive**, so they repel. The attraction is between the **shared (negative) electrons** and the **two positive nuclei**. Source: Edexcel Chemistry examiner reports

Why is "Forgetting the word 'electrostatic' when explaining bond strength" a common mistake in Formation of covalent bonds?

Why it happens: Students describe attraction but not the type of force. How to avoid it: Always state it is a **strong electrostatic attraction** — the specific word 'electrostatic' is mark-bearing. Source: Edexcel Chemistry examiner reports

Why is "Saying covalent bonding makes ions, or that electrons are transferred" a common mistake in Formation of covalent bonds?

Why it happens: Confusion between covalent and ionic bonding. How to avoid it: Covalent = **shared** (no ions, molecule is neutral). Ionic = **transferred** (ions form). Use the right verb for each. Source: Edexcel Chemistry examiner reports

Why is "Mixing up 'shared pairs' and 'shared electrons' (e.g. saying a double bond has 2 electrons)" a common mistake in Formation of covalent bonds?

Why it happens: 'Pair' and 'electron' are used loosely. How to avoid it: Each pair = **2** electrons. Double bond = 2 pairs = **4** electrons; triple bond = 3 pairs = **6** electrons. Source: Edexcel Chemistry examiner reports

Why is "Classifying a metal-containing compound (e.g. NaCl, MgO) as covalent" a common mistake in Formation of covalent bonds?

Why it happens: Students focus on the non-metal and ignore the metal in the formula. How to avoid it: A **metal + non-metal** compound is **ionic**. Covalent bonding is only between **non-metals**. Check for a metal first. Source: Edexcel Chemistry examiner reports

Ionic bondingEdexcel IGCSE Science(Double Award)-Chemistry (4WSD0-1C)

Formation of covalent bonds

Work through the notes, try the practice questions, then take the quiz. The report tells you exactly what to revise next.

Previous Next

Learn this Topic

Start with the slides for the quick version, then go deeper with the full study notes.

Detailed Notes

Full prose, callouts and a recap — built for A* mastery, not just a quick scan.

Take these study notes with you

Download a branded PDF — full prose, callouts, recap and memorise list for Formation of covalent bonds, ready to print or save offline.

Formation of Covalent Bonds — Edexcel International GCSE Science (Double Award) Chemistry (4WSD0-1C) Study Notes

How two non-metal atoms SHARE a pair of electrons to form a covalent bond, why that bond is a strong electrostatic attraction between the shared electrons and the two nuclei, and how to tell covalent from ionic. Covers Double Award Chemistry spec 1.56–1.57, assessed on Chemistry Paper 1 (4WSD0/1C).

What you’ll learn

Mapped to the Edexcel IGCSE 4WSD0-1C syllabus (2026 onwards).

1.56 — Understand that a covalent bond is formed when a pair of electrons is shared between two atoms.
1.57 — Understand that a covalent bond is a strong electrostatic attraction between the shared electrons and the two nuclei.

What is a covalent bond? (spec 1.56)

A shared pair of electrons — one electron from each atom.

A covalent bond is a shared pair of electrons between two atoms. It forms between non-metal atoms (for example two hydrogens, or hydrogen and chlorine, or oxygen and oxygen).

Why do atoms share? Most atoms do not have a full outer shell on their own. A full outer shell is stable (it matches a noble gas). Instead of giving electrons away, two non-metals each give one electron to a shared pair. Both atoms can then "count" that shared pair as part of their own outer shell — so both end up with a full, stable outer shell.

Take the simplest example, hydrogen, H₂:

Each hydrogen atom has 1 electron but needs 2 to fill its outer shell.
Neither atom can spare an electron, so they share instead.
Each atom contributes 1 electron to make a shared pair.
Now each H has access to 2 electrons → both outer shells are full. A molecule of H₂ has formed.

The outer shells overlap and one pair of electrons (one from each atom) is shared — that shared pair is the covalent bond.

Mark-scheme wording. The examiner wants the exact phrase "a shared pair of electrons". Saying "the atoms share electrons" or "they join up" is too vague to score the full mark.

Covalent bond = a SHARED PAIR of electrons.
Forms between non-metal atoms.
One electron from each atom makes the shared pair.
Both atoms gain a full, stable outer shell.

See the full worked example for formation of covalent bonds →

Why a covalent bond is strong (spec 1.57)

Electrostatic attraction between the shared electrons and BOTH nuclei.

A covalent bond is a strong bond. To explain why, you must use the idea of electrostatic attraction — the attraction between opposite charges.

The shared pair of electrons sits between the two atoms. Electrons are negatively charged.
The nucleus of each atom is positively charged.
The negative shared pair is attracted to both positive nuclei at the same time.
This attraction pulls the two atoms together and holds them in place — that is the bond.

Both positive nuclei attract the shared (negative) pair — a strong electrostatic attraction that holds the atoms together.

The exam answer for "why is a covalent bond strong?" must contain three ideas:

there is a strong electrostatic attraction,
between the shared pair of electrons (negative),
and the two (positive) nuclei of the bonded atoms.

Common trap. Do not say "the atoms are attracted to each other" — both nuclei are positive, so they would repel. The attraction is between the shared electrons and the nuclei, not between the two nuclei.

A covalent bond is a STRONG electrostatic attraction.
Between the shared (negative) pair of electrons…
…and the two (positive) nuclei of the bonded atoms.
The two nuclei are NOT attracted to each other (both positive).

See the full worked example for formation of covalent bonds →

Single, double and triple bonds (spec 1.56)

Count the shared pairs: 1 → single, 2 → double, 3 → triple.

Atoms do not always need to share just one pair. Some atoms share more than one pair with the same partner so that both can reach a full outer shell.

Bond type	Shared pairs	Shared electrons	Examples
Single	1	2	H–H, H–Cl, O–H bonds in water
Double	2	4	O=O (in O₂), C=O (in CO₂)
Triple	3	6	N≡N (in N₂)

A single bond is one shared pair (2 electrons).
A double bond is two shared pairs (4 electrons), shown as =.
A triple bond is three shared pairs (6 electrons), shown as ≡.

Counting tip. Each shared pair = 2 electrons. So a double bond means 4 shared electrons, and a triple bond means 6 shared electrons. If an exam asks "how many shared pairs are in N₂?" the answer is 3 (it is a triple bond).

Strength order. More shared pairs = a stronger bond, so triple > double > single. This is one reason nitrogen gas (N₂, with a triple bond) is so unreactive.

Single bond = 1 shared pair (2 electrons).
Double bond = 2 shared pairs (4 electrons), e.g. O=O.
Triple bond = 3 shared pairs (6 electrons), e.g. N≡N.
More shared pairs = stronger bond (triple > double > single).

See the full worked example for formation of covalent bonds →

Covalent versus ionic — sharing or transfer?

Look at the elements: two non-metals = covalent; metal + non-metal = ionic.

Students lose easy marks by confusing covalent and ionic bonding. The quickest way to decide is to look at the elements involved.

	Covalent	Ionic
Atoms involved	non-metal + non-metal	metal + non-metal
What happens to electrons	shared	transferred (given/taken)
Particles made	neutral molecules	charged ions (⁺ and ⁻)
Examples	H₂, Cl₂, H₂O, CO₂, CH₄	NaCl, MgO, CaCl₂

In covalent bonding, electrons are shared — each atom keeps its own electron and gains a share of another, so no charges form and the molecule is neutral overall.
In ionic bonding, electrons are transferred completely — a metal atom loses electrons to become a positive ion, and a non-metal atom gains them to become a negative ion. The bond is the attraction between oppositely charged ions.

Quick test: is there a metal in the formula?

No metal (all non-metals) → likely covalent.
Metal present → likely ionic.

Watch the wording. For covalent, the key word is SHARED; for ionic, it is TRANSFERRED. Examiners deliberately check that you use the right word — writing "shared" for an ionic bond (or "transferred" for a covalent one) loses the mark.

Covalent = two non-metals SHARE electrons → neutral molecules.
Ionic = metal + non-metal TRANSFER electrons → charged ions.
Quick test: a metal in the formula points to ionic.
Use the word SHARED for covalent, TRANSFERRED for ionic.

See the full worked example for formation of covalent bonds →

How it’s examined

Double Award Chemistry is assessed on one untiered paper — Chemistry Paper 1 (4WSD0/1C), 2 hours, 110 marks, 33.3% of the Double Award (calculator allowed). Formation of covalent bonds appears as define/explain marks: define a covalent bond as a 'shared pair of electrons' (1–2 marks), explain why a covalent bond is strong using 'electrostatic attraction between the shared electrons and the two nuclei' (2 marks), count shared pairs in single/double/triple bonds, and classify substances as covalent or ionic from the elements involved. The biggest discriminator is the strength explanation — naming both nuclei and the shared (negative) electrons.

Sources: Pearson Edexcel International GCSE Science (Double Award) 4SD0 specification — Issue 4 (valid for 2026 onwards); Pearson Edexcel International GCSE Chemistry 4CH1 specification — Issue 4 (shared Chemistry Paper 1 content); Pearson Edexcel 4SD0 / 4CH1 examiner reports 2022–2024. Last reviewed 2026-06-07.

Master this Topic

Worked examples, formulae, definitions and the mistakes examiners flag — everything you need to push from a pass to an A*.

Take this whole topic with you

Download a branded revision sheet — worked examples, formulae, definitions and common mistakes for Formation of covalent bonds, ready to print or save as PDF.

Step-by-step worked examples — Formation of covalent bonds

Step-by-step solutions to past-paper-style questions on formation of covalent bonds, written exactly the way a tutor would explain them at the board.

1Define a covalent bond (Getting started)
Getting started• 4WSD0/1C style — short answer• covalent, spec-1.56
Question
State what is meant by the term 'covalent bond'. (1 mark)
Step-by-step solution
1. Step 1
  Recall the exact definition (1). A covalent bond is a shared pair of electrons (between two atoms).
2. Step 2
  Use the key phrase. The mark scheme looks for the words 'shared pair of electrons' — 'atoms share electrons' is too vague.
Answer
A covalent bond is a shared pair of electrons between two atoms.
Examiner tip
One mark, but it is all-or-nothing on the phrase 'shared pair of electrons'. Vague answers like 'when atoms join together' score zero.
2Count the shared pairs (Getting started)
Getting started• 4WSD0/1C style — short answer• single-double-triple, spec-1.56
Question
State the number of shared pairs of electrons in: (a) a single bond; (b) a double bond; (c) a triple bond. (3 marks)
Step-by-step solution
1. Step 1
  (a) Single bond (1). A single bond is 1 shared pair of electrons.
2. Step 2
  (b) Double bond (1). A double bond is 2 shared pairs of electrons.
3. Step 3
  (c) Triple bond (1). A triple bond is 3 shared pairs of electrons.
Answer
(a) 1 shared pair; (b) 2 shared pairs; (c) 3 shared pairs.
Examiner tip
Each shared pair is 2 electrons, so a double bond = 4 shared electrons and a triple bond = 6. Watch the wording: 'pairs' is not the same as 'electrons'.
3Decide covalent or ionic from the elements (Building confidence)
Building confidence• 4WSD0/1C style — structured• covalent-vs-ionic, spec-1.56, application
Question
For each substance, state whether the bonding is covalent or ionic, and give a reason: (a) Cl₂; (b) MgO; (c) CH₄. (3 marks)
Step-by-step solution
1. Step 1
  (a) Cl₂ — covalent (1). Chlorine is a non-metal; two non-metal atoms share electrons, so the bonding is covalent.
2. Step 2
  (b) MgO — ionic (1). Magnesium is a metal and oxygen a non-metal; a metal + non-metal transfer electrons to form ions, so the bonding is ionic.
3. Step 3
  (c) CH₄ — covalent (1). Carbon and hydrogen are both non-metals, so they share electrons → covalent.
Answer
(a) Cl₂ covalent (two non-metals share electrons); (b) MgO ionic (metal + non-metal transfer electrons to form ions); (c) CH₄ covalent (two non-metals share electrons).
Examiner tip
The fastest decision rule: a metal in the formula → ionic; all non-metals → covalent. Always justify with 'share' (covalent) or 'transfer' (ionic).
4Explain why a covalent bond is strong (Building confidence)
Building confidence• 4WSD0/1C style — structured• bond-strength, spec-1.57
Question
Explain, in terms of the particles involved, why a covalent bond is a strong bond. (2 marks)
Step-by-step solution
1. Step 1
  Identify the attraction (1). There is a strong electrostatic attraction between the shared pair of electrons (negative) and the two nuclei (positive).
2. Step 2
  Name both nuclei (1). The shared pair is attracted to both nuclei of the bonded atoms at the same time, holding the atoms together.
3. Step 3
  Avoid the trap. Do not say the two nuclei attract each other — both are positive and would repel. The attraction is electrons ↔ nuclei.
Answer
A covalent bond is a strong electrostatic attraction between the shared pair of electrons (negative) and the two positive nuclei of the bonded atoms.
Examiner tip
Both marks need: 'electrostatic attraction' + the shared electrons AND the two nuclei. Missing 'electrostatic' or only naming one nucleus drops a mark.
5Explain how a covalent bond forms in HCl (Stretch)
Stretch• 4WSD0/1C style — extended• formation, spec-1.56, reasoning
Question
Hydrogen chloride, HCl, is a covalent molecule. Explain how a covalent bond forms between a hydrogen atom and a chlorine atom, and why this gives both atoms a stable arrangement. (4 marks)
Step-by-step solution
1. Step 1
  Each atom contributes (1). The hydrogen atom and the chlorine atom each provide one electron.
2. Step 2
  Shared pair forms (1). These two electrons form a shared pair between the two atoms — this is the covalent bond.
3. Step 3
  Hydrogen stable (1). By sharing, hydrogen now has access to 2 electrons → a full outer shell (like helium).
4. Step 4
  Chlorine stable (1). Chlorine now has access to 8 electrons in its outer shell → a full (stable) outer shell (like a noble gas).
Answer
Hydrogen and chlorine each provide one electron, which form a shared pair (the covalent bond). Sharing gives hydrogen a full outer shell of 2 electrons and chlorine a full outer shell of 8 electrons, so both atoms become stable.
Examiner tip
Full marks need: each atom gives one electron + a shared pair forms + both atoms reach a full/stable outer shell. State the number (2 for H, 8 for Cl) to be unambiguous.
6Classify several substances and justify (Stretch)
Stretch• 4WSD0/1C style — extended• covalent-vs-ionic, spec-1.56, data
Question
A student is given four substances: O₂, NaCl, H₂O and CaO. (a) Identify the two with covalent bonding. (b) Explain the difference between how electrons behave in a covalent bond and in an ionic bond. (4 marks)
Step-by-step solution
1. Step 1
  (a) Pick the covalent ones (1 + 1). O₂ (oxygen, a non-metal, with itself) and H₂O (hydrogen and oxygen, both non-metals) have covalent bonding. NaCl and CaO each contain a metal, so they are ionic.
2. Step 2
  (b) Covalent behaviour (1). In a covalent bond, electrons are shared between the atoms — a shared pair attracted to both nuclei; no charged particles form.
3. Step 3
  (b) Ionic behaviour (1). In an ionic bond, electrons are transferred from the metal to the non-metal, forming positive and negative ions that attract each other.
Answer
(a) O₂ and H₂O are covalent. (b) In covalent bonding electrons are shared (a shared pair between the atoms, no ions form); in ionic bonding electrons are transferred from metal to non-metal, forming oppositely charged ions that attract.
Examiner tip
Part (b) is a classic 'compare' answer — the contrast must be explicit: SHARED (covalent) versus TRANSFERRED (ionic), and 'no ions' versus 'ions form'.

Model Answers — Formation of covalent bonds

High-scoring sample answers for formation of covalent bonds on the Pearson Edexcel IGCSE Chemistry Paper 1 (4WSD0/1C) paper, with examiner-style notes mapping each response to the mark scheme and assessment objectives.

Question 1
4WSD0/1C style2 marks
What is meant by a 'covalent bond'? (2 marks)
Model answer
A covalent bond is a shared pair of electrons (1)

between two atoms (usually two non-metal atoms). (1)
Why this scores
The phrase 'shared pair of electrons' secures the first mark; identifying it as between two (non-metal) atoms secures the second. 'Atoms share electrons' alone is borderline.
Question 2
4WSD0/1C style4 marks
State the number of shared pairs of electrons and the number of shared electrons in a double bond and in a triple bond. (4 marks)
Model answer
Double bond — 2 shared pairs (1) = 4 shared electrons. (1)

Triple bond — 3 shared pairs (1) = 6 shared electrons. (1)
Why this scores
Each shared pair is 2 electrons, so multiply by 2. A common slip is to write '2 electrons' for a double bond — that is the number of pairs, not electrons.
Question 3
4WSD0/1C style4 marks
Explain why a covalent bond is described as a strong bond. (4 marks)
Model answer
A covalent bond is a strong electrostatic attraction. (1)

The shared pair of electrons is negatively charged. (1)

Each nucleus of the bonded atoms is positively charged. (1)

The shared pair is attracted to both nuclei at the same time, pulling the atoms together and holding them in place. (1)
Why this scores
Marks for: electrostatic attraction; shared electrons are negative; nuclei are positive; attraction acts on BOTH nuclei. Do not claim the two nuclei attract each other — they are both positive and repel.
Question 4
4WSD0/1C style4 marks
Compare covalent bonding and ionic bonding by stating, for each, the type of atoms involved and what happens to the electrons. (4 marks)
Model answer
Covalent bonding:

forms between two non-metal atoms; (1)

electrons are shared (a shared pair), so neutral molecules form (no ions). (1)

Ionic bonding:

forms between a metal and a non-metal; (1)

electrons are transferred from the metal to the non-metal, forming positive and negative ions. (1)
Why this scores
The discriminators are the words SHARED (covalent) versus TRANSFERRED (ionic), and the type of atoms (non-metals only versus metal + non-metal). Mixing the two up is the most common way to lose marks here.
Question 5
4WSD0/1C style — extended6 marks
Water, H₂O, is made of covalent molecules. Explain how covalent bonds form in a water molecule and why this makes both the oxygen and the hydrogen atoms stable. (6 marks)
Model answer
Oxygen is a non-metal and hydrogen is a non-metal, so they share electrons rather than transfer them. (1)

The oxygen atom forms a covalent bond with each of the two hydrogen atoms — two single bonds in total. (1)

In each bond, the oxygen atom and a hydrogen atom each contribute one electron to make a shared pair. (1)

This shared pair is the covalent bond: a strong electrostatic attraction between the shared electrons and the nuclei of O and H. (1)

Each hydrogen now has access to 2 electrons → a full outer shell (stable, like helium). (1)

The oxygen now has access to 8 electrons in its outer shell → a full (stable) outer shell (like a noble gas). (1)
Why this scores
Top band needs: non-metals so they share; two O–H bonds; one electron from each atom forms a shared pair; both H reach 2 electrons and O reaches 8. State the electron numbers explicitly — vague 'they become stable' caps the mark.
Question 6
4WSD0/1C style — extended6 marks
A nitrogen molecule, N₂, contains a triple bond. (a) State how many shared pairs of electrons there are in this bond. (b) Explain, in terms of attraction, why this triple covalent bond is very strong. (6 marks)
Model answer
(a) A triple bond contains 3 shared pairs of electrons (= 6 shared electrons). (1)

(b)

A covalent bond is a strong electrostatic attraction between the shared electrons (negative) and the two positive nuclei. (1)

In a triple bond there are three shared pairs of electrons between the two nuclei. (1)

This means there is a greater amount of negative charge shared between the atoms. (1)

The two positive nuclei are therefore attracted more strongly to the shared electrons than in a single or double bond. (1)

So a triple bond is the strongest of the three (triple > double > single), which is why N₂ is very unreactive. (1)
Why this scores
Part (b) rewards linking the NUMBER of shared pairs to the STRENGTH of the electrostatic attraction. Stating the order triple > double > single and connecting it to N₂'s unreactivity secures the top band.

Key Definitions and Keywords — Formation of covalent bonds

Definitions to memorise and the exact keywords mark schemes credit for formation of covalent bonds answers — sharpened from recent examiner reports for the 2026 Pearson Edexcel IGCSE Chemistry Paper 1 (4WSD0/1C) sitting.

Covalent bond
Examiner keyword
A shared pair of electrons between two atoms. The bond is a strong electrostatic attraction between the shared electrons and the two nuclei.
Shared pair of electrons
Examiner keyword
Two electrons (one from each atom) that are shared between two bonded atoms and count towards both atoms' outer shells.
Electrostatic attraction
Examiner keyword
The attractive force between opposite charges — here, between the negative shared electrons and the positive nuclei of the bonded atoms.
Nucleus
The small, positively charged centre of an atom. In a covalent bond, both nuclei attract the shared pair of electrons.
Single bond
Examiner keyword
A covalent bond made of one shared pair of electrons (2 shared electrons).
Double bond
Examiner keyword
A covalent bond made of two shared pairs of electrons (4 shared electrons), e.g. O=O.
Triple bond
A covalent bond made of three shared pairs of electrons (6 shared electrons), e.g. N≡N.
Molecule
A particle made of two or more atoms held together by covalent bonds; it is neutral overall (no charge).
Non-metal
An element (such as hydrogen, carbon, oxygen or chlorine) whose atoms form covalent bonds by sharing electrons with other non-metals.
Ionic bond (for contrast)
A bond formed when electrons are transferred from a metal to a non-metal, producing oppositely charged ions that attract — contrast with covalent sharing.

Common Mistakes and Misconceptions — Formation of covalent bonds

The traps other students keep falling into on formation of covalent bonds questions — taken from recent Pearson Edexcel IGCSE Chemistry Paper 1 (4WSD0/1C) examiner reports and mark schemes — and how to avoid them.

✕Defining a covalent bond as 'when atoms share electrons' instead of 'a shared pair of electrons'
Edexcel Chemistry examiner reports — recurring error
Why it happens
Students remember the idea of sharing but drop the mark-scheme phrase.
How to avoid it
Write the exact phrase: 'a shared pair of electrons'. The word pair is essential for the mark.
✕Saying a covalent bond is 'the attraction between the two nuclei (atoms)'
Edexcel Chemistry examiner reports
Why it happens
Students know there is an attraction but point it at the wrong particles.
How to avoid it
Both nuclei are positive, so they repel. The attraction is between the shared (negative) electrons and the two positive nuclei.
✕Forgetting the word 'electrostatic' when explaining bond strength
Edexcel Chemistry examiner reports
Why it happens
Students describe attraction but not the type of force.
How to avoid it
Always state it is a strong electrostatic attraction — the specific word 'electrostatic' is mark-bearing.
✕Saying covalent bonding makes ions, or that electrons are transferred
Edexcel Chemistry examiner reports
Why it happens
Confusion between covalent and ionic bonding.
How to avoid it
Covalent = shared (no ions, molecule is neutral). Ionic = transferred (ions form). Use the right verb for each.
✕Mixing up 'shared pairs' and 'shared electrons' (e.g. saying a double bond has 2 electrons)
Edexcel Chemistry examiner reports
Why it happens
'Pair' and 'electron' are used loosely.
How to avoid it
Each pair = 2 electrons. Double bond = 2 pairs = 4 electrons; triple bond = 3 pairs = 6 electrons.
✕Classifying a metal-containing compound (e.g. NaCl, MgO) as covalent
Edexcel Chemistry examiner reports
Why it happens
Students focus on the non-metal and ignore the metal in the formula.
How to avoid it
A metal + non-metal compound is ionic. Covalent bonding is only between non-metals. Check for a metal first.

Past paper style quiz

Get a report showing which sub-topics you've nailed and which ones still need work.

Formation of covalent bonds

Detailed Notes

What you’ll learn

How it’s examined

1Define a covalent bond (Getting started)

2Count the shared pairs (Getting started)

3Decide covalent or ionic from the elements (Building confidence)

4Explain why a covalent bond is strong (Building confidence)

5Explain how a covalent bond forms in HCl (Stretch)

6Classify several substances and justify (Stretch)

Covalent bond

Shared pair of electrons

Electrostatic attraction

Nucleus

Single bond

Double bond

Triple bond

Molecule

Non-metal

Ionic bond (for contrast)

✕Defining a covalent bond as 'when atoms share electrons' instead of 'a shared pair of electrons'

✕Saying a covalent bond is 'the attraction between the two nuclei (atoms)'

✕Forgetting the word 'electrostatic' when explaining bond strength

✕Saying covalent bonding makes ions, or that electrons are transferred

✕Mixing up 'shared pairs' and 'shared electrons' (e.g. saying a double bond has 2 electrons)

✕Classifying a metal-containing compound (e.g. NaCl, MgO) as covalent

Past paper style quiz