Chemistry

• What is a control variable?

  A factor that stays the same during the experiment
• What are the four state symbols?

  s,l,g,aq
• What is the chemical formula for chlorine?

  $Cl_2$
• What is the chemical formula for Hydrogen?

  $H_2$
• What’s the chemical formula for Ammonia?

  $NH_3$
• Who made the plum pudding model?

  J J Thompson
• Who described atoms as solid spheres?

  John Dalton (earliest)
• Who fired alpha particles through a thin sheet of gold?

  Ernest Rutherford
• Who proposed a new model of the atom that suggested electrons were contained in shells?

  Niels Bohr
• What’s the charge of a proton?

  1+, Positive
• What’s the charge of neutrons?

  0, neutral
• What’s the charge of an electron?

  -1, negative
• What’s is the radius of an atom?

  $10^{-10}M$
• What is the overall charge of atoms?

  Neutral, same number of protons and electrons
• What does the atomic number tell you? (Bottom number)

  How many protons there are
• What does the mass number tell you? (top number)

  Total number of protons and neutrons
• What is a compound?

  A combination of atoms from at least 2 different elements
• What are 4 key features of a chemical reaction?

  Compounds broken up or formed

  At least 1 new substance created

  Measurable energy change

  No atoms created or destroyed
• How do you balance equations?

  Write out the equation and split it into reactants and products, next you need to count the number of elements on each side. Then add numbers in front to balance each side with the same amount of elements.
• What was John Dalton’s model?

  In 1803, Dalton suggested that all matter is made of atoms and cannot be split.
• What was J.J Thompson’s model?

  The plum pudding model - a ball of positively charged ‘dough’ with small plums in to represent the electrons.
• What was Ernest Rutherford’s model?

  The gold foil experiment - Rutherford discovered that alpha particles could bounce back off of atoms, he concluded that an atoms mass is concentrated in its centre in a positively charged nucleus.
• What was Niels Bohr and James Chadwick’s model?

  The modern model - Bohr discovered that electrons orbited the nucleus at fixed distances.

  Chadwick discovered that some particles in the nucleus have no charge, he called them neutrons.
• What is the charge of a neutron?

  What is its RAM?

  -1

  Approximately 0
• What is the charge of a neutron?

  What is its RAM?

  0

  1
• What is the charge of a proton?

  What is its RAM?

  1

  1
• How do you work out relative formula mass?$^Mr$


  Work out how many atoms of each element there are in the chemical formula.

  Add together the$^Ar$ values (RAM)
• How many elements have been discovered?

  118
• What is the smallest piece of an element?

  Atoms
• What is a compound?

  A substance that contains at least 2 different elements
• What are key features of a chemical reaction?

  Compounds are broKen up or formed

  At least 1 new substance created

  Measurable energy change

  No atoms are created or destroyed
• Where are reactants found in an equation?

  On the left
• Where are products found in an equation?

  On the right
• Who suggested that all matter is made of atoms which cannot be split?

  John Dalton
• Who suggested the plum pudding model, and discovered electrons?

  J.J. Thomson
• Who suggested the gold foil test, discovered protons and found that an atoms mass is concentrated in a ‘nucleus’?

  Ernest Rutherford
• Who discovered that electrons orbit a nucleus at fixed distances?

  Niels Bohr
• Who discovered neutrons?

  James Chadwick
• What is the charge of a proton?

  +1
• What is the RAM (Ar) of a proton?

  0