Chapter 3: Atomic structure The structure of atoms 1. Use the words in the box to complete the gaps below. Use each word only once. Missing words: atom, charge, compound, electrons, element, mass, molecules, nucleus, neutrons, orbit, positive, relative Atoms are the smallest particle it is still possible to recognise as an_______. Atoms are made of three types of particle: protons, neutrons and ________. Protons have a relatively ___________ charge and have a relative ______ of 1. Protons are located in the _________ of an atom. Also in the nucleus are the _______. Neutrons have a relative mass of 1 just like protons but they do not have any ________. Around the nucleus are the electrons which _____ the nucleus in shells or orbitals. The electrons have a _________ charge of -1 and have a relative mass of 1/1832. Atoms can join to form ____________. Molecules can be made of the same _________ or of different atoms. If the molecule is made of different atoms it is said to be a ____________. Atomic number and mass number 2. Use your knowledge of atomic number and mass number to complete the table below. Element Carbon Aluminium Argon Potassium Atomic number Number of neutrons 6 14 19 Number of electrons 6 13 18 Mass number 12 27 40 39 Isotopes 3. In the space below write a definition of the term isotope. _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ Relative atomic mass 4. A new element is discovered that is found as two different isotopes. 6XX accounts for 14% of the new elements isotopes found. The other isotope is 7XX which occurs 86% of the time. Using this information calculate the relative atomic mass of new element in the space below. Show your working. © Pearson Education Ltd 2018. Copying permitted for purchasing institution only. This material is not copyright free.