C1

• Charge of a nucleus

  Positive charge because of protons
• Electrons


  Move around the nucleus in electron shells and are negatively charged
• Relative charges of protons, neutrons and electrons

  Proton : 1

  Neutron : 1

  Electron : very small , almost 0
• Relative mass of protons , neutrons and electrons

  Protons : +1

  Neutrons : 0

  Electrons : -1
• Atomic number 


  The number of protons in an atom
• Atomic mass


  The total number of protons and neutrons in an atom
• Element 


  An element is a substance that only contains one type of atom and it can't be broken
• Isotope 


  An isotope is an element with the same number of protons but a different number of neutrons
• Examples of an isotope

  Carbon-12 Carbon-13

  6 protons 6 protons

  6 electrons 6 electrons

  6 neutrons 7 neutrons
• Relative Atomic Mass 


  Is an average mass taking into account the different masses and abundances of all isotopes that make up an element
• Formula for Relative Atomic Mass


  Relative Atomic Mass =sum of (isotope abundance x isotope mass No)

  -------------------------------------------

  sum of abundance of all isotopes
• Compound 


  A compound is a substance formed from 2 or more elements that are chemically bonded together
• A compound formed from chemical reactions

  carbon + oxygen --> carbon dioxide
• Rutherford model of the atom


  Rutherford's model was the nuclear model.He used the alpha particle experiment and found that some particles passed through , some deflected and some deflected backwards
• How did Rutherford prove the plum pudding model was wrong ?


  From the plum pudding model, they expected particles tom pass through.Most particles went through, some passed through empty space
• What did Niels Bohr model suggest?

  Niels Bohr's model suggested that all electrons were contained in shells and he proposed that electrons orbit the nucleus in fixed shells
• What did James Chadwick discover?

  James Chadwick carried an experiment that provided evidence for neutral particles in the nucleus
• How many electrons can be on each outer shell?

  2 on the first shell

  8 on the second shell

  8 on the third shell
• What happens when metals react?

  When metals react they can form positive ions
• Where are metals on the periodic table?

  They are on the left side of the periodic table , towards the bottom
• What happens when non-metals react?

  Non-metals dont form positive ions
• How do atoms react to form a full outer shell?

  They share , lose or gain electrons to form a full outer shell
• Why do metals at the bottom of the periodic table have a weak attraction?

  The outer shell electrons are further away from the nucleus
• Why do non-metals have a strong attraction?

  Non-metals feel a strong attraction because they are close to the nucleus so it is easier for them to either share or gain electrons to get a full outer shell
• Properties of metals 


  Metals are strong , hard to break but can be bent , they have a high melting and boiling points and they are good conductors of heat and electricity
• Properties of non-metals


  Non-metals have a low density , are brittle and are poor conductors of heat and electricity
• Mixture 


  A mixture consists of different substances that are not chemically bonded together
• Filtration


  Removes large insoluble particles from a liquid
• Evapouration


  Evapouration leaves behind crystals of a dissolved substance if its heated gently
• Distillation


  Distillation is condensing evapourated solvent and collecting it
• Fractional distillation


  Fractional distillation can separate liquids due to their different boiling points
• Chromotography 


  Chromotography causes substances to rise up paper due to cappilary action and light particles move further up
• Mendeleev's periodic table


  Mendeleev left gaps for undiscovered elements

  He switched the orders of some elements and arranged elements in order of atomic mass
• Modern periodic table

  Elements are arranged in order of atomic number

  They are organised in groups and periods

  Elements with similar chemical properties are grouped together in groups
• What did John Dalton describe atoms as ?

  Solid spheres and different spheres made up different elements