C3a Structure Of The Atom


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C3a Structure Of The Atom

  1. 1. C3a What are Atoms Like? What is an atom? What is the structure of an atom? • Atoms are made up from a central ___________ that is orbited by __________ • The nucleus is made up of ________________ and ____________________. • So, atoms are made up from 3 sub-atomic particles; ______________, _______________ and _____________________. What are protons, neutrons and electrons? sub-atomic particle charge mass protons neutrons electrons IMPORTANT FACT An atom always has an ____________ number of ________________ (+) and ________________ (-). This means that they have no overall charge – we say that they are ______________________. How can we work out the number of protons, neutrons and electrons in an atom?
  2. 2. • Each different type of atom is a different ______________ and has a different number of ____________, ____________ and ______________. • Everything on Earth is made up from about _________ different elements and they are listed on the periodic table: 23 Consider Sodium Each element can be found in its own square. Find sodium and copy the information into this box: What can we tell from this information? Na sodium Tasks
  3. 3. 1. Using a periodic table, find the symbol and the atomic number for: a) Helium b) Potassium c) Iron d) Copper e) Bromine 2. Complete the following table: Name Symbol Atomic Number Mass Number Lithium Li 3 7 Carbon Calcium Aluminium Iron 3. Now calculate the number of protons, neutrons and electrons in one atom of each element from the table above. Remember: Atomic number = number of protons (there must be an equal number of electrons) Mass number = number of protons + neutrons Name Number of protons Number of neutrons Number of Electrons Lithium 3 7-3 = 4 3 Carbon Calcium Aluminium Iron How are elements arranged in the Periodic Table? Find the following elements, in order, Hydrogen Helium Lithium
  4. 4. Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium What do you notice about the atomic numbers and atomic masses of these elements? Give as much detail about any trends (patterns) that you spot. Answer in bullet points.
  5. 5. Scientists use isotopes to carbon-date dinosaur bones and other fossils. Isotopes • Isotopes are different varieties of the same element. • Isotopes have: the same __________________ but different _______________ or the same number of ___________ but different numbers of _______ • Carbon is an element that has 2 isotopes called carbon-12 and carbon-14 Carbon-12 Carbon-14 12 14 6 C 6 C Number of: protons = neutrons = electrons = Important: The neutrons do not affect the __________________________ of an element so different _____________________ of an element perform EXACTLY THE SAME chemical reactions they are just heavier. Task Hydrogen has 3 isotopes. They have mass numbers of 1, 2 and 3. Calculate the number of protons, neutrons and electrons for all 3 different isotopes of hydrogen.
  6. 6. Compounds • An element is a substance which: 1. 2. • A compound is a substance that contains at _____ or more _________ chemically bonded together. • You must be able to identify the elements in a compound from its formula, using a periodic table e.g. CuSO4 contains: _____ atom of the element copper, Cu _____ atom of the element sulphur, S _____ atoms of the element oxygen, O Task Identify which elements make up the following compounds and how many atoms of each element there are. The first one is done as an example (it continues on the next page. a) MgO f) C6H12O6 Mg Magnesium – 1 atom O Oxygen – 1 atom b) K2O g) Al2O3 c) CO2 h) Fe(OH)2
  7. 7. d) NaOH i) KCr2O7.6H2O e) P2O5 j) CuSO4.5H2O Electronic Structure • The electronic structure shows us how electrons are arranged in an atom. • Electrons occupy the space around the _______________. • Electrons ___________ the nucleus in _____________ (sometimes called energy levels). • Electrons must fill the ________ shell, which is closest to the nucleus before they can start to fill the _______ shell. • The 1st shell can hold a maximum of _____ electrons The 2nd shell can hold a maximum of _____ electrons The 3rd shell holds a maximum of _____ electrons before starting the 4th shell. e.g. sodium has 11 electrons so the electronic arrangement for sodium is: Calcium has 20 electrons so the electronic arrangement for calcium is: For your exam:
  8. 8. You must be able to deduce the electronic structure of the first 20 elements in the periodic table e.g. calcium is Element Atomic Electronic Structure Group Number Number H 1 no number He 2 Li 3 Be 4 B 5 C 6 N 7 O 8 F 9 Ne 10 Na 11 Mg 12 Al 13 Si 14 P 15 S 16 Cl 17 Ar 18 K 19 Ca 20 What do pattern do you notice in the number of electrons in the outer shell and the group number of each element?