C1.1- ELEMENTS AND THE PERIODIC TABLE

C1.1- ELEMENTS AND THE PERIODIC TABLE

1. THE ATOM

   • Contain neutrons and protons in the nucleus
   • Electrons on the electron shell
   • Proton Charge- +1 Postive
   • Neutron Charge- 0 Neutral
   • Electron Charge- -1 Negative
   • Different atoms have different numbers of protons, neutrons and electrons
   • Number of protons decide what type of atom it is
   • Contains ONE type of atom- Element
   • Each atom contains a small, positively central region- the NUCLEUS
   • Every atom of a particular element has the same number of protons. Number of protons- ATOMIC NUMBER.

2. MENDELEEV

   • First person to describe the Periodic Table that ordered the elements by increasing atomic weight and according to trends in their properties
   • Presented his table based on increasing atomic weight on March 6, 1869 in a presentation to the Russian Chemical Society.
   • His table was the first to gain some acceptance in the scientific community
   • When he organised the table into horizontal rows, a pattern became apparent- but only if he left blanks in the table
   • Suggested that new elements not yet discovered would be found to fill the blanks
   • Predicted the properties of the missing properties
   • MODERN PERIODIC TABLE- Orders the elements according to increasing atomic number rather than increasing atomic weight

3. THE PERIODIC TABLE

   • We use the atomic number and the mass number to show the composition of the atom
   • The atom doesn't have an electrical charge because it has the same number of protons in the nucleus as there are electrons orbiting it
   • Atom LOSES an electron- shortage of negative charge. Atom is more POSITIVE. Overall Positive Charge. Positive ion.
   • Atom GAINS an electron, too much negative charge. Atom is more NEGATIVE. Overall Negative Charge. Negative Ion
   • Atomic Number of an atom- how many protons in the nucleus, how many electrons the atom has
   • Electrons are arranged according to: Maximum of two electrons in the first orbit, Maximum of eight for all other orbits, Always fill the orbits from the middle out

4. METALS AND NON-METALS

   • PROPERTIES OF METALS
     • Conduct electricity and heat
     • Strong and sonorous
     • High melting and boiling points
     • Malleable and ductile
     • High density
     • Shiny and form positive ions
   • PROPERTIES OF NON-METALS
     • Don't conduct electricity or heat
     • Brittle and Not Sonorous
     • Low melting and boiling points
     • Not malleable or ductile
     • Low density, not shiny and form negative ions
   • The elements change from metals to non-metals across the Periodic Table. Metals- Left. Non-Metals- Right

5. KEY FOCUS POINT FOR REVISION

   • Comparing Mendeleev's Table and Today's
   • Properties of Metals/ Non-Metals
   • Be able to spot/use 'trends'