C1 Atomic Models

L3 Atomic Model Monday, September 17, 2018 Learning Objectives Key Words Describe how and why the atomic model has changed over time. (grade 4-5) Describe the difference between the plum-pudding model of the atom and the nuclear model of the atom. (grade 6-7) atom, nuclear, plum pudding, discovery, Bohr, Chadwick, Rutherford, Dalton AQA New Science

Starter Discuss with your partner about what you already know about atomic structure Look back in books too!

Recap: Atoms What are the 3 subatomic particles in atoms? What are each of their charges and relative masses? What is in the centre of the atom ? nucleus neutron proton electron

Today’s lesson

Some key facts… New experimental evidence may lead to a scientific model being changed or replaced. Before the discovery of the electron atoms they were thought to be tiny spheres that could not be divided.

Atomic Model THE PLUM-PUDDING MODEL THE NUCLEAR MODEL There are two main types of the model that you need to know about: THE PLUM-PUDDING MODEL THE NUCLEAR MODEL You will need to know who the scientists related to each model are – and what they represent

Plum-Pudding Model summary The discovery of the electron led to the plum-pudding model of the atom. The plum-pudding model suggested that the atom was a ball of positive charge with negative electrons embedded in it. The results from the Rutherford and Marsden’s alpha scattering experiments led to the plum-pudding model being replaced by the nuclear model.

Nuclear Model summary The model states that the atom consists of a dense positive centre called the nucleus and is orbited by negatively charged electrons. The nuclear model of the atom was first proposed by New Zealand scientist Ernest Rutherford while working in England under J. J. Thomson.

Atomic Model Timeline https://www.youtube.com/watch?v=NSAgLvKOPLQ (10mins) Watch the clip and note down some info in your books

Atomic Model Scientists Remember, the HIGHER worksheet is double-sided Atomic Model Scientists Now: time for your scientist cards! Form groups with the other students whose Superhero (scientist) card information shares the same identifying colour. You will be given an A3 sheet to complete Around the room there are information handouts on each scientist listed on the worksheets. Complete the A3 sheet in a group . When you have the correct answers, take an A4 version of the sheet of your own and fill in the gaps with the correct answers. eg

Atomic Model Timeline Stick in the timeline

Lesson Summary! Fill the gaps in!

Lesson Summary! Can you fill the gaps in?? Think Pair Share with your partner! Then write the answers on your handout The discovery of the electron led to the plum pudding model of the atom. Before the discovery of the electron atoms were thought to be tiny spheres that could not be divided. Rutherford and Marsden’s alpha scattering experiments led to the plum pudding model being replaced by the nuclear model. Niels Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus at specific distances. The theoretical calculations of Bohr agreed with experimental observations. Later experiments led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge. The name proton was given to these particles. In 1932 the experimental work of Chadwick provided the evidence to show the existence of neutrons within the nucleus.

Homework Complete the questions booklet on atom models. Due in NEXT LESSON! NO excuses Web link to hwk here

Plenary HAVE YOU BEEN A SUCCESSFUL LEARNER? Write a-d in your books Plenary HAVE YOU BEEN A SUCCESSFUL LEARNER? WHAT GRADE DID YOU END THE LESSON ON? HAVE YOU MET YOUR TARGET GRADE? CHOOSE A LEARNING OUTCOME STATEMENT & EXPLAIN IT The Outcomes from today: Describe how and why the atomic model has changed over time. (4-5) Describe the difference between the plum-pudding model of the atom and the nuclear model of the atom. (6-7)