C1 EXPECTATIONS 1.Dont talk when the teacher is talking 2.Respect others in the classroom 3.Ask questions if you are unsure 4.Complete all homework on time KEYWORDS: atom, element, periodic table Understand the structure of atoms ALL state what is meant by an atom MOST Describe how elements are formed SOME Explain where most of the mass in an atom is Starter Draw what the particles in a solid, liquid and gas look like What is an atom? An atom is the smallest amount of a substance that you can possibly have In Y7, Y8 and Y9, you might have called atoms particles. However, the proper term for them is atoms LO: understand the structure of atoms Elements A substance that is made of just one type of atom is called an element. There are over 100 different elements that have already been discovered and more are still being discovered now. LO: understand the structure of atoms The Periodic Table LO: understand the structure of atoms The periodic table shows all the elements that have been discovered so far Representing elements LO: understand the structure of atoms An element is represented using a symbol. This symbol is either one or two letters. The first letter is ALWAYS A CAPITAL. e.g. Sodium = Na (not na) Oxygen = O (not o) Fluorine = F (not f) Potassium = K Iron = Fe Mercury = Hg Magnesium = Mg Ernest Rutherford LO: understand the structure of atoms For a long time, scientists believed that there was nothing smaller than atom. It took a scientist called Ernest Rutherford to prove that atoms were, in fact, made of smaller particles themselves. The structure of an atom LO: understand the structure of atoms Rutherford showed that an atom is made up of three smaller particles: Protons Neutrons Electrons The structure of an atom LO: understand the structure of atoms Protons and neutrons are in the centre of the atom called the nucleus. The electrons orbit around the nucleus. The structure of an atom LO: understand the structure of atoms In each atom, the number of protons will ALWAYS be the same as the number of electrons. This makes sure that the overall charge is zero. ParticleCharge Proton+1 Neutron0 Electron The structure of an atom LO: understand the structure of atoms Minutes Start Timer State the three particles that make up an atom What is the charge on each of the particles that make up an atom? Explain why an atom is neutral KEYWORDS: atom, element, periodic table Understand how to interpret the periodic table ALL state the definition of mass and atomic number MOST Calculate the number of protons and electrons in an atom SOME Draw electron sub-shell diagrams The periodic table LO: understand how to interpret the periodic table Closer inspection of the periodic table shows us that each element has two numbers next to it. What do these numbers represent? Atomic and Mass number LO: understand how to interpret the periodic table Atomic number: This is the number of protons inside the nucleus of an atom Mass number: This is the number of protons + neutrons in the nucleus of an atom Atomic and Mass number LO: understand how to interpret the periodic table Atomic number: This is the number of protons inside the nucleus of an atom Mass number: This is the number of protons + neutrons in the nucleus of an atom Atomic and Mass number LO: understand how to interpret the periodic table The Atomic number is ALWAYS the smaller number next to the element. The mass number is always the bigger number. Example 1 Calculate the following quantities for the element below (i)Atomic number (ii)Mass number (iii)Number of protons (iv)Number of electrons (v)Number of neutrons LO: understand how to interpret the periodic table Example 2 Calculate the following quantities for the element below (i)Atomic number (ii)Mass number (iii)Number of protons LO: understand how to interpret the periodic table Example 3 Calculate the following quantities for the element below (i)Atomic number (ii)Mass number (iii)Number of neutrons LO: understand how to interpret the periodic table Isotopes Elements can exist in more than one form. They have the same atomic number but different mass numbers. These are called ISOTOPES LO: understand how to interpret the periodic table Electron shells Consider Calcium. Calcium has an atomic number of 20. All of calciums 20 electrons can NOT fit in one orbit. Therefore, there must be multiple orbits for electrons to occupy LO: understand how to interpret the periodic table Shell break down Atoms have 4 shells where electrons can live Shell 1 2 electrons Shell 2 8 electrons Shell 3 8 electrons Shell 4 Whatever is left! LO: understand how to interpret the periodic table Example Electron arrangement for oxygen LO: understand how to interpret the periodic table Task Draw the electron arrangement for potassium. It has an atomic number of 12 LO: understand how to interpret the periodic table Task Draw the electron arrangement for hydrogen. It has an atomic number of 1 LO: understand how to interpret the periodic table Mini-plenary Create a mind-map about everything that you have learnt about atoms, elements and the periodic table so far LO: understand how to interpret the periodic table