###### Worksheets and lesson ideas to challenge students aged 11 to 16 to think hard about atomic structure and isotopes (GCSE and Key Stage 3)

*This interesting clip by Ian Stewart challenges our current thinking about when students should be taught atomic theory. In this school, young primary students enjoy learning about atomic structure.*

*A useful way to approach the teaching of atomic structure is to consider the changing models proposed by scientists throughout history. The image here could represent a sequence of lessons on atomic theory, starting with a simple billiard ball model at Key Stage 2 and ending with the electron cloud model at A Level. *

#### General teaching resources on the particle theory (solids, liquids and gases)

Resources to help students understand particles are found elsewhere

#### Structure of the nucleus: protons and neutrons

GCSE worksheet on atomic structure. This activity allows students to discover how the atomic number and mass number relate to the proton, electron and neutron numbers. Students work in groups to spot patterns in nucleon and electron numbers. They construct an understanding of atomic structure for themselves. (PDF)

GCSE worksheet on atomic structure key words. Key words used to describe atomic structure are written on the board. Students come up with a list of questions that their partner must answer by using the key words written on the slide. This activity promotes good discussion between students and supports meaning making of key terms. (PDF)

#### Electronic configuration of atoms

Whenever teaching atomic structure, it is vital students gain an understanding of scale and just how empty atoms are. This fantastic model helps students appreciate the scale of a hydrogen atom

GCSE worksheet on electronic configuration and the Periodic table. Students draw on the electronic configuration for the first 20 elements. They see for themselves how group number equals valence electron number. (PDF)

Follow this link for a GCSE activity where students have to decide if a model shows an atom or an ion.

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Isotopes

Students need to understand and explain why isotopes have the same chemical properties but different physical properties. Heavy water can provide an excellent context to study isotopes. Ice cubes of heavy water sink in water. Perhaps get students to Predict, Observe and Explain what is happening in the video below from 6:14. Then move on to get students to calculate the relative atomic mass for hydrogen. Why is it not simply an average of the three naturally occurring isotopes ^{1}H, ^{2}H, and ^{3}H i.e. 2 and not 1.00794?

#### The development of the model of the atom

GCSE worksheet on the development of the model of the atom. Students read about the development of the model of the atom throughout history and draw what they think the atom would have looked like at different points in time. Students then consider what was right and what was wrong about each model. The Phet animation of Rutherford’s scattering experiment will be useful to students. (PDF)