2.1+Atomic_Structure.pptx

SUBJECT: SCIENCE YEAR: Y9 DIGNITY TOPIC: ATOMIC STRUCTURE Atomic Structure Learning Objectives: Do I know.. The structure of an atom? About the relative size of the nucleus? That atoms of a given element have the same number of protons in the nucleus? The meaning of the terms ‘atomic number’ a...

SUBJECT: SCIENCE YEAR: Y9 DIGNITY TOPIC: ATOMIC STRUCTURE Atomic Structure Learning Objectives: Do I know.. The structure of an atom? About the relative size of the nucleus? That atoms of a given element have the same number of protons in the nucleus? The meaning of the terms ‘atomic number’ and ‘mass number’?  What is an atom made of? All matter is made up of particles called atoms. These atoms are made up of even simpler sub-atomic particles. These are called protons, electrons, and Challenge neutrons. Draw the diagram to the left. Can you add these labels? Nucleus Proton Neutron Electron shells Electron  What is an atom made of? At the centre of an atom is a positive nucleus. If the atom was the size of the O2 arena, the nucleus would be the size of a table tennis ball! The nucleus is made up of positive protons, and neutral neutrons. The nucleus is surrounded by electrons. These electrons are arranged in layers, or shells, sometimes these shells are called energy levels. Electron Nucleus Electron Shells Proton Neutron  What is an atom made of? Complete your table using the information about sub-atomic particles around the room. Particle Relative Relative Where in the Charge Mass atom is it found? Proton +1 1 In the nucleus Neutron 0 1 In the nucleus Electron -1 Almost 0 In shells (actually surrounding 0.0005) the nucleus Valence Electrons  The number of valence electrons an atom has may also appear in a square.  Valence electrons are the electrons in the outer energy level of an atom.  These are the electrons that are transferred or shared when atoms bond together. Atomic number and mass number So far scientists have identified 118 different types of atom. This means there are 118 different elements. Each element has a fixed number of protons in its nucleus. Look at Lithium (Li) on your Periodic Table (page 120 of your planner). Atomic number and mass number Lithium looks like this on the table, this is known as the ‘nuclear symbol.’ We know that This is the atomic number for lithium. 3 the ‘Li’ is the Li chemical This number tells us how many protons are in the nucleus. symbol for No other element has the same atomic 7 lithium, but number as lithium. what do those This is the mass number. The mass numbers number of an atom mean? is the total number of protons and neutrons in the Atomic number and mass number You can use the nuclear symbol for an atom to work out the number of protons and neutrons in the nucleus. The nuclear symbol for Phosphorus (P) is shown below. How many protons and neutrons are in its nucleus? 15 P 31 Atomic number and mass number The atomic number is 15. This is the number of 15 protons in the nucleus. 31 P The mass number is 31. This is the total number of protons and neutrons in the nucleus. So, 31 – 15 = 16. Test Yourself 1. Using the nuclear symbols shown for these atoms, write down the numbers of protons and neutrons 16 in the nucleus of 23 each atom. 8 O 11 Na 2. An atom of potassium (K), has 19 protons and 20 neutrons in its nucleus. Write down the nuclear symbol for this atom. Electron configuration