🌱 *G.C.E. O/L Science – Day 06*
📚 *Unit 03 – Structure of Matter*
📖 *Lesson – Electron Configuration, Isotopes and the Periodic Table*
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*❓ Question 01:*
What is meant by electron configuration?
> ✅ *Answer:*
> It is the arrangement of electrons in the energy levels of an atom, in order from the nucleus towards the outside.
*❓ Question 02:*
How are the main energy levels in an atom, in which electrons are arranged, represented?
> ✅ *Answer:*
> They are represented by the letters K, L, M and N.
*❓ Question 03:*
What is the maximum number of electrons that can be present in the K energy level?
> ✅ *Answer:*
> 2 electrons.
*❓ Question 04:*
What is the maximum number of electrons that can be present in the L energy level?
> ✅ *Answer:*
> 8 electrons.
*❓ Question 05:*
State the maximum numbers of electrons that can be present in the M and N energy levels respectively.
> ✅ *Answer:*
> M = 18, N = 32.
*❓ Question 06:*
Write the electron configuration of an oxygen atom with atomic number 8.
> ✅ *Answer:*
> 2, 6.
*❓ Question 07:*
Write the electron configuration of a sodium (Na) atom with atomic number 11.
> ✅ *Answer:*
> 2, 8, 1.
*❓ Question 08:*
Write the electron configuration of a chlorine (Cl) atom with atomic number 17.
> ✅ *Answer:*
> 2, 8, 7.
*❓ Question 09:*
What is the electron configuration of an argon (Ar) atom with atomic number 18?
> ✅ *Answer:*
> 2, 8, 8.
*❓ Question 10:*
What is the electron configuration of a calcium (Ca) atom with atomic number 20?
> ✅ *Answer:*
> 2, 8, 8, 2.
*❓ Question 11:*
Which atoms are called isotopes?
> ✅ *Answer:*
> Atoms of the same element having the same atomic number but different mass numbers are called isotopes.
*❓ Question 12:*
What atomic characteristic is the same in isotopes?
> ✅ *Answer:*
> The number of protons is the same.
*❓ Question 13:*
Which subatomic particle differs between two isotopes?
> ✅ *Answer:*
> The number of neutrons differs.
*❓ Question 14:*
Why are ¹⁶O and ¹⁸O oxygen atoms considered isotopes?
> ✅ *Answer:*
> Because they have the same atomic number but different mass numbers.
*❓ Question 15:*
How are letters used when writing an element symbol?
> ✅ *Answer:*
> The first letter is written as a capital letter. If there is a second letter, it is written as a lowercase letter.
*❓ Question 16:*
Write the symbols of the elements with atomic numbers 1 to 5 in order.
> ✅ *Answer:*
> H, He, Li, Be, B.
*❓ Question 17:*
What is a horizontal row in the Periodic Table called?
> ✅ *Answer:*
> It is called a period.
*❓ Question 18:*
What is a vertical column in the Periodic Table called?
> ✅ *Answer:*
> It is called a group.
*❓ Question 19:*
Name the two elements in the first period.
> ✅ *Answer:*
> Hydrogen (H) and Helium (He).
*❓ Question 20:*
State two basic factors used when classifying elements in the Periodic Table.
> ✅ *Answer:*
> Atomic number and electron configuration.
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🎯 *DAY 06 COMPLETED!*
📌 *EXAM TIP:*
> *K = 2 | L = 8 | M = 18 | N = 32*
> *O = 8 → 2,6*
> *Na = 11 → 2,8,1*
> *Cl = 17 → 2,8,7*
> *Ca = 20 → 2,8,8,2*
> *Isotopes → Same atomic number, different mass number.*
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