Atomic Structure and development of the atom

Engager Think, Pair and Share… True or False…? Atoms cannot be split up into anything smaller. Atoms are solid objects and nothing can pass through them. There are millions of different kinds of atoms. No-one has ever seen an atom. False! False! False! False!

To understand how the structure of the atom has changed To evaluate the different types of models of the atom. To suggest why models have changed in science. To explain the different sub atomic particles. Progress

To demonstrate good progress in this lesson Name Will… To suggest why models have changed in science. To explain the different sub atomic particles The Honley Learning Mindset Advocate for this lesson is… Matthew – will show resilience by not giving up if he finds something difficult.

Recap - The Structure of the Atom There are many different models used to describe the structure of an atom. In this model the electrons are shown orbiting around a central nucleus. However, electrons also possess properties typical of waves.

The Structure of the Atom There are many different models used to describe the structure of an atom. In this model the electrons are shown orbiting around a central nucleus. However, electrons also possess properties typical of waves.

Atomic structure definition Click on the You tube link if needed

Atomic number Number of protons Number of electrons Mass Number Number of protons + Number of neutrons ALWAYS THE BIGGER ONE! 4 2 He Atomic number Number of protons Number of electrons Segway ito information on the periodic table, students must be able to identify these numbers. Hand out periodic tables and have students find the correct number of sub atomic particles in 5 elements

H H H What is going on here? 1 2 1 3 1 1 proton 1 proton 1 proton 1 electron Refer to the balance needed between the numbers of protons and neutrons for an atom to be stable, they don’t have to be equal numbers but there is a ‘required mix for stability line’. The further away from this ‘line’ the isotope is the more radioactive it is likely to be. 1 electron 1 electron 0 NEUTRONS 1 NEUTRON 2 NEUTRONS

Can you and your partner come up with a definition for an isotope? What’s an isotopes? Link in the baseball team from the simpsons and why it is called the isotopes Can you and your partner come up with a definition for an isotope?

Definition of an Isotopes Talk through the idea that the further away from the ídeal’ they are.. The more unstable they will be and thus radioactive Same number of protons and electrons, different neutrons

Sub Atomic Particles - Check What You Know For each particle drag and drop the correct answers into the table.

Connector -Why do models in Science change ?

Plum pudding model of the atom One of the first models of the atom was by J J Thompson and he knew the atom was neutral and had no charge and he also showed that they contain electrons which were negatively charged Positively charged sphere Negatively charged electron This became known as the ‘plum pudding’ model.

Earnest Rutherford E. Rutherford (1871 - 1937) In 1910, Earnest Rutherford’s team carried out experiments in which particles were fired at a thin sheet of gold. Rutherford expected all of the particles to pass straight through...

Earnest Rutherford Press ‘Start’ to take a closer look at Rutherford’s experiment... Rutherford also predicted the existence of neutrons in the nucleus, and named the three types of nuclear radiation alpha (), beta () and gamma ().

Earnest Rutherford experiment Click on the You tube link for explanation

What Rutherford’s team observed…….. Most of the alpha particles went straight through the foil. Some alpha particles were deflected through large angles. 3. A very few alpha particles were reflected straight back.

Rutherford’s conclusions Observation Conclusion Most alpha particles went straight through the foil. A few were deflected through large angles. A very few were reflected straight back. Atoms are mostly space. The nucleus is very small compared to the size of the atom and it contains most of the mass and all the positive charge.

Comprehension exercise – Complete the sheet given by going around the room and finding the information. Teacher another student an aspect of what you have found out

Atomic structure (Physics) Relative charges; Keywords; proton, neutron, electron, nucleus, orbital/shell, plum pudding model, Niels Bohr, alpha particle, positive, negative, models James Chadwick, relative mass, relative charge, isotope, atomic number, mass number, electronic configuration, Atoms, elements & compounds Relative charges; Compounds; Are formed by elements in chemical reactions Are 2 or more elements that are chemically combined Atoms; Atomic number; The proton number, it is different for every element Atoms; Elements; There are about 100 different elements, each with a symbol Isotopes; Size and mass; Very small, radius is 0.1nm (1x10-10m) Mass is mainly in the nucleus Mass Number; Early ideas; Before the discovery of the electron atoms were tiny spheres, they couldn’t be divided Development of the model of the atom; Electronic configurations; Nucleus development; Experiments now show nucleus is made of smaller particles of positive charge Relative Atomic Mass; This is the mass of the element that takes into account the relative abundance of isotopes, Calculated by= (mass x abundance) + (mass x abundance) 100 Plum pudding; Niels Bohr; Adapted the nuclear model suggesting electrons in orbitals at set distance James Chadwick; Evidence to show the existence of neutrons in the nucleus Atomic structure (Physics) Alpha particle scattering; Showed that the mas of an atom was concentrated in the centre, it was charged too

Atomic structure (Physics) Relative charges; Keywords; proton, neutron, electron, nucleus, orbital/shell, plum pudding model, Niels Bohr, alpha particle, positive, negative, models James Chadwick, relative mass, relative charge, isotope, atomic number, mass number, electronic configuration, percentage abundance, periodic table, Atoms, elements & compounds Relative charges; Compounds; Are formed by elements in chemical reactions Are 2 or more elements that are chemically combined Atoms; An atom has no overall charge, the number of protons = the number of electrons Atomic number; The proton number, it is different for every element Atoms; Everything is made of atoms, it is the smallest part of an element Elements; There are about 100 different elements, each with a symbol Isotopes; Atoms that have the same number of protons (element), but different numbers of neutrons Size and mass; Very small, radius is 0.1nm (1x10-10m) Mass is mainly in the nucleus Mass Number; The number of protons & neutrons in the nucleus Early ideas; Before the discovery of the electron atoms were tiny spheres, they couldn’t be divided Development of the model of the atom; New experimental evidence may lead to the model being changed or replaced Electronic configurations; Electrons fill the lowest energy levels first This starts from the nucleus, following a set pattern up to the following maximum 1st shell – 2 electrons 2nd shell – 8 electrons 3rd shell – 8 electrons 4th shell – 2 electrons Nucleus development; Experiments now show nucleus is made of smaller particles of positive charge Relative Atomic Mass; This is the mass of the element that takes into account the relative abundance of isotopes, Calculated by= (mass x abundance) + (mass x abundance) 100 Plum pudding; After the electron was discovered the atom became a ball of positive charge with negative electrons scattered in it Niels Bohr; Adapted the nuclear model suggesting electrons in orbitals at set distance James Chadwick; Evidence to show the existence of neutrons in the nucleus Atomic structure (Physics) Alpha particle scattering; Showed that the mas of an atom was concentrated in the centre, it was charged too

Homework – GCSE Question on Ernest Rutherford's experiment