DSE Chemistry: Atomic Structure and the Periodic Table

DSE Chemistry: Atomic Structure and the Periodic Table — Tutor Lesson Plan

2026-10-27

Tutor lesson-prep guides · Secondary chemistry

Students can recite 2,8,8 but do not see that the arrangement is the coordinate on the periodic table. This lesson connects arrangement, period, group and ion.

Objectives — the student can write an electronic arrangement from the atomic number, read off period and group, and predict simple ion charges.

01 Prerequisites (3-minute check)

If any of these fails, fix it before the lesson starts.

Skill	Quick check	Pass mark
Particles	Name the three subatomic particles	Proton, neutron, electron
Atomic number	What does it count?	Protons
Symbols	Symbols for sodium and chlorine	Na, Cl

02 Lesson flow (60 minutes)

Time	Stage	Tutor does	Student does
0-10 min	Three numbers	Atomic number, mass number, neutrons	Five calculations
10-26 min	Arrangement	The 2,8,8 rule	Sodium and chlorine
26-42 min	Arrangement to table	Shells give period, outer electrons give group	Place five elements
42-54 min	Ions	Lose or gain electrons	Three ions
54-57 min	Notation	Symbol plus charge	Correct the notation
57-60 min	Exit check	Three questions marked	Finish alone

03 Teaching script (read it out)

Scene 1: Keep the three numbers apart

Atomic number is the proton count; mass number is protons plus neutrons.
Sodium has 11 and 23, so 12 neutrons. In a neutral atom electrons equal protons.

Student calculates chlorine 17 and 35: 18 neutrons.

Scene 2: The arrangement is the table coordinate

Sodium 2,8,1: three shells, so period 3; one outer electron, so group 1.
Chlorine 2,8,7: period 3, group 7.

Student places magnesium 12 (2,8,2).

Scene 3: Ions reach a full outer shell

Sodium loses one electron to become Na⁺ with 2,8.
Chlorine gains one to become Cl⁻ with 2,8,8.
Charge goes top right, number before the sign.

Warn: write Na⁺, not Na+1.

04 Question types and worked steps

Type	Example	Steps	Answer
Neutrons	sodium 11, 23	23 – 11	12
Arrangement	chlorine 17	2, 8, 7	2,8,7
Period and group	magnesium 12	2,8,2	Period 3, group 2
Ion	oxygen 8	2,6 gains two	O²⁻

Sanity check (teach this): The charge must match the electrons gained or lost: oxygen gains two electrons, so the charge is 2-.

05 Independent practice (3 questions)

Question	Answer	What to watch
Neutrons in chlorine (17, 35)	18	35 minus 17
Arrangement of magnesium	2,8,2	12 electrons
Sodium ion arrangement and charge	2,8 and +1	Loses one outer electron

06 Common mistakes and what to say

Mistake	Student writes	Say this
Atomic and mass number mixed	uses 23 as electrons	Electrons equal protons.
More than 8 in a shell	writes 2,9	The outer shell holds 8.
Charge in the wrong place	Na+1	Write Na⁺.
Period and group swapped	sodium called period 1 group 3	Shells give the period.

07 Homework (paper, section and question numbers)

Secondary chemistry chapter index — Use the three questions on this page

08 Exit check (last 5 minutes)

Question	Answer	Decision
Neutrons in sodium (11, 23)	12	All right: move to bonding
Arrangement of chlorine	2,8,7	One wrong: re-teach arrangement
Ion of oxygen	O²⁻	Two wrong: repeat scene 3

09 Tutor FAQ

Memorise the first twenty elements?

Atomic numbers and symbols, yes; the rest follow from arrangements.

Transition metals?

Recognise only for DSE.

Link to bonding?

Ion charges drive ionic formulae, so this chapter is the base.

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A TutorZone lesson-prep guide. Written by the TutorZone team; questions and lesson flow are original and are not taken from any school or publisher material.