C4

C4

1. Atom structure

   • nucleus surrounded by electrons
     • nucleus has a positive charge, electrons have a negative charge, overall the atom has no charge as they cancel eachother out.
       • atomic number: number of protons in an atom: written below on periodic table
       • Mass number: number of an atom is the total number of protons and neutrons in an atom
       • Relative masses: neutron-1, proton-1 ,electron-0
       • subtracting atomic number from mass number gives us amount of neutrons, if atom neutral No of protons equal No of electrons.
   • isotopes
     • atoms with the same atomic number but different mass numbers, due to different amounts of neutrons (still neutral)
     • if a electron or neutron is lost then a charge is gained rather

2. Compounds

   • if two elements combine together (chemically) a compound is made.
   • A compound has to have a minimum of two elements.
   • electron arrangement
     • electrons occupy shells around the nucleus, the pattern of No of electrons in shells 2.8.8.10
     • Dalton had the theory of electrons in shells but his idea was only provisional but as time went on different scientists (Rutherford, Thompson and Bohr) found evidence to support and improve his thesis. all there concepts were provisional as they still didn't have all the evidence to prove it.

3. electronic structure

   • max number of electrons per shell and atomic number needed to figure out structure

4. Ionic Bonding

   • atoms are the smallest particles that can bond
   • an ion is a charged atom or a group of atoms (with a charge)
     • negative or positive chaarge
   • a molecule has more than one atom in its formula and no charge
   • atoms with a full outer shell of electrons are stable, atoms either have too few or too many electrons in there outer shell.
     • if the atoms loses atoms to complete its shell then it a metal
     • if atoms gain electrons to complete its shell its a non-metal
     • if an electron is gained or lost an ion is made

5. Periodic table

   • elements are arranged in columns and rows. the rows represent how many shells the atom has, the columns mean how many atoms are on the outer shell

6. the development of atom theory and periodic table

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