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ScienceGCSE chemistry: atomic structure and bonding30 min★★★ difficulty

Atomic structure and the periodic table

The arrangement of electrons explains the whole periodic table: why groups behave alike and why trends run down them.

Lesson overview

What you'll learn in this lesson

Relate atomic structure and bonding to the properties of substances.

Key learning points

  • • Inside the atom
  • • Electronic structure
  • • Group trends

This lesson at a glance

  • 30 minutes
  • 16 parts to scroll through
  • 4 quick checks
  • Marked quiz at the end
  • Gentle pace: short sittings with pauses

Words to know

relateatomicstructurebondingproperties

Scroll down — the lesson carries on below

Part 1 of 16 · Discover6%
1

Watch & discover

Part 1 of 16

Watch first

Atomic structure and the periodic table

An English teaching video on this topic from Science Workshop. Watch it, then scroll down for the lesson.

In a nutshell

Relate atomic structure and bonding to the properties of substances.

2

Learning cycle

Part 2 of 16

Learning cycle 1 of 2

Part 1 · Inside the atom

A short piece of teaching, then a check to make sure it has landed.

3

Explore the idea

Part 3 of 16

Learn

Inside the atom

Protons have relative charge +1 and mass 1, neutrons 0 and 1, electrons −1 and negligible mass. Atomic number is the number of protons and defines the element; mass number is protons plus neutrons. Isotopes are atoms of the same element with different numbers of neutrons, so they share chemical properties.

4

Explore the idea

Part 4 of 16

Learn

Electronic structure

Electrons occupy shells holding 2, 8, 8 for the first twenty elements, so sodium is 2,8,1. The number of outer electrons equals the group number and determines chemical behaviour, while the number of occupied shells gives the period.

5

Quick check

Part 5 of 16

Quick check

Atomic number is the number of

6

Quick check

Part 6 of 16

Quick check

Isotopes differ in the number of

7

Reset break

Part 7 of 16

Pause

That's sitting 1 of 2 done

Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.

Stop here for now
8

Learning cycle

Part 8 of 16

Learning cycle 2 of 2

Part 2 · Group trends

A short piece of teaching, then a check to make sure it has landed.

9

Explore the idea

Part 9 of 16

Learn

Group trends

Group 1 metals become more reactive down the group, because the outer electron is further from the nucleus and more shielded, so it is lost more easily. Group 7 non-metals become less reactive down the group, for the mirror reason: gaining an electron becomes harder. Group 0 gases are unreactive because their outer shells are full.

10

Quick check

Part 10 of 16

Quick check

Sodium's electronic structure is

11

Quick check

Part 11 of 16

Quick check

Group 0 elements are unreactive because they have

12

Explore the idea

Part 12 of 16

Worked example

Worked answer: explain why potassium is more reactive than lithium (3 marks)

Both are group 1 metals with one outer electron, and their reactions involve losing it (1). Potassium's outer electron is in a shell further from the nucleus and is shielded by more inner shells, so the attraction between the nucleus and that electron is weaker (1). The electron is therefore lost more easily, making potassium the more reactive metal (1). 'Potassium is bigger' alone earns nothing without the effect on attraction.

13

Challenge round

Part 13 of 16

Game · Sort it

Which of these are true?

Drag each card into the right column. Tap a card first if dragging is fiddly.

True

Not true

14

Challenge round

Part 14 of 16

Game · Fill the gaps

Finish the sentences

Choose the word that belongs in each gap.

____ number is the number of protons and defines the element; mass number is protons plus neutrons.

Isotopes are atoms of the same element with different numbers of neutrons, so they share chemical ____.

15

Mastery quiz

Part 15 of 16

Marked quiz

End of lesson quiz: Atomic structure and the periodic table

4 questions, marked with the reasoning shown. No timer.

  1. 1. Atomic number is the number of

  2. 2. Isotopes differ in the number of

  3. 3. Sodium's electronic structure is

  4. 4. Group 0 elements are unreactive because they have

16

Lesson round-up

Part 16 of 16

Lesson round-up

Ready when you are

Quiz score

Not sat

Games

Not played

Points this lesson

0

Best run

0 in a row

Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?

Ask Luna

Do the work

Your written work for this lesson

This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.

Case study

Why the school greenhouse failed

A science club grew tomato plants in the school greenhouse. In June the plants grew well: leaves were dark green and the fruit set quickly. In July the club went away for two weeks and left the greenhouse door shut. When they came back, the leaves were curled and pale and most of the fruit had dropped.

The club had a data logger inside. It showed the temperature reached 46 °C on several afternoons and the soil moisture fell close to zero. The club knew photosynthesis needs light, water and carbon dioxide, and that enzymes in a plant work best in a narrow range of temperature. Above that range the enzymes stop working properly.

The club repeated the summer with the door propped open and a water bottle drip on each pot. Temperature peaked at 31 °C and the plants survived.

Written for Good Learning Co.

Reading questions

  1. Name the variable the club changed the second time, and one variable they kept the same.
  2. Explain, using the words photosynthesis and enzymes, why the plants were damaged in July.
  3. Write a conclusion for the club's report, saying how far the evidence supports it.

  • Method and results

    Writing

    Write the aim, what you changed, what you measured and what you kept the same, then record your results in a table.

    1 page + results table

  • Conclusion

    Writing

    Explain what your results show and why, using the scientific words from the lesson. Say how you know you can trust them.

    6–8 sentences

  • Labelled diagram

    Diagram

    Draw the apparatus or the process in pencil, label it fully, and photograph it.

    1 labelled diagram

  • Reading and notes

    Reading

    Read the lesson text again and write the key ideas in your own words.

    Half a page of notes

Saved as you type.

Part 1 of 16 · Watch & discover

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