Atomic number = Number of protons = Number of electrons
Valency = Number of valence electrons or 8 - Number of valence electrons
Ionization energy = Energy required to remove an electron from an atom
Electron ga∈ enthalpy = Energy change when an electron is added to an atom
Oxidation number = Number of electrons gained or lost by an atom
Reactivity series: Series of metals arranged ∈ order of their reactivity
Metals: High melting and boiling points, malleable, ductile, good conductors of heat and electricity
Non-metals: Low melting and boiling points, brittle, poor conductors of heat and electricity

🪤 The 5 Mistakes That Cost Marks

Not understanding the difference between metals and non-metals
Not knowing the reactivity series of metals
Not understanding the concept of valency and oxidation number
Not being able to identify the physical properties of metals and non-metals
Not being able to write the chemical reactions of metals and non-metals

✏️ 3 Solved PYQs

What is the electronic configuration of sodium? Step 1: Sodium is ∈ group 1 of the periodic table Step 2: The electronic configuration of sodium is 1s² 2s² 2p⁶ 3s¹
Why are metals good conductors of electricity? Step 1: Metals have free electrons that can move freely Step 2: These free electrons carry electrical charge and conduct electricity
What is the reaction of magnesium with oxygen? Step 1: Magnesium is a highly reactive metal Step 2: The reaction of magnesium with oxygen is 2Mg + O₂ → 2MgO

🧠 The One Thing Most Students Get Wrong

Most students get the reactivity series of metals wrong
The correct order of reactivity is: Potassium (K) > Sodium (Na) > Calcium (Ca) > Magnesium (Mg) > Aluminum (Al) > Zinc (Zn) > Iron (Fe) > T∈ (Sn) > Lead (Pb) > Copper (Cu) > Mercury (Hg) > Silver (Ag) > Gold (Au)
This is important for predicting the outcome of chemical reactions involving metals

👁️ Ayush's Note

To score well ∈ the CBSE Board 2026 exam, make sure to practice plenty of MCQs and long-answer questions
Focus on understanding the concepts of metals and non-metals, including their physical and chemical properties
Make a list of important formulas and reactions, such as the reactivity series and the electronic configuration of atoms
Use the exam compass to navigate the question paper and manage your time effectively

🔁 Last 5 Minutes Box

Quickly review the reactivity series of metals
Check the electronic configuration of atoms, especially for sodium, magnesium, and aluminum
Make sure to remember the physical properties of metals and non-metals, such as melting and boiling points, malleability, and conductivity
Review the chemical reactions of metals and non-metals, including oxidation and combustion reactions
Use the remaining time to fill ∈ any gaps ∈ your knowledge and reinforce your understanding of key concepts

📝 Practice MCQs

1. Which of the following is a characteristic of metals?

A) Low melting and boiling points

B) Brittle and poor conductors of heat and electricity

C) High melting and boiling points, malleable, and good conductors of heat and electricity

D) Highly reactive and easily corroded

Answer: C) High melting and boiling points, malleable, and good conductors of heat and electricity

2. What is the electronic configuration of magnesium?

A) 1s² 2s² 2p⁶

B) 1s² 2s² 2p⁶ 3s²

C) 1s² 2s² 2p⁶ 3s¹

D) 1s² 2s² 2p⁶ 3s² 3p¹

Answer: B) 1s² 2s² 2p⁶ 3s²

3. Which of the following metals is most reactive?

A) Potassium (K)

B) Sodium (Na)

C) Calcium (Ca)

D) Magnesium (Mg)

Answer: A) Potassium (K)

4. What is the reaction of aluminum with oxygen?

A) 2Al + O₂ → 2AlO

B) 4Al + 3O₂ → 2Al₂O₃

C) Al + O₂ → AlO

D) 2Al + O₂ → Al₂O

Answer: B) 4Al + 3O₂ → 2Al₂O₃

5. Which of the following non-metals is a good conductor of electricity?

A) Carbon ( C) - B) Nitrogen (N)

C) Oxygen (O)

D) None of the above

Answer: D) None of the above

🚀 Ready to Ace Your Exam?

Put your knowledge to the test! Take the free Practice Mock Test now and track your progress against thousands of students.

🎬 Watch video explanations on YouTube →

This post was curated by Jules, Exam Compass Bot, and edited for accuracy by Ayush.

📚 Related Topics

Continue your revision with these related guides:

Atomic number = Number of protons = Number of electrons
Valency = Number of valence electrons or 8 - Number of valence electrons
Ionization energy = Energy required to remove an electron from an atom
Electron ga∈ enthalpy = Energy change when an electron is added to an atom
Oxidation number = Number of electrons gained or lost by an atom
Reactivity series: Series of metals arranged ∈ order of their reactivity
Metals: High melting and boiling points, malleable, ductile, good conductors of heat and electricity
Non-metals: Low melting and boiling points, brittle, poor conductors of heat and electricity