atoms, ions and compounds

Question 1

what is Daltons atomic model

Answer 1

• atoms are solid spheres
• different types of spheres are made of different elements

Question 2

what is Thomson’s atomic model

Answer 2

-positively charged sphere with negatively charged electrons embedded in it
-plum pudding model

Question 3

what is Rutherford’s atomic model

Answer 3

• gold foil experiment
• nuclear model of the atom
• most of the atom is empty space
• tiny positively charged atom at the centre of an atom

Question 4

what modifications where there to rutherfords model

Answer 4

• Mosely discovered the charge of nucleus changed with every element
  -Rutherford discovered nucleus contained protons
  -Chadwick discovered neutrons that explained why nucleus was heavier than it would be if it contained only protons

Question 5

what is Bohr’s atomic model

Answer 5

-electrons only exist in fixed orbits (shells)
-each shell has fixed energy
- when electron travels shells electromagnetic radiation is emitted or absorbed
-because shells energy is fixed radiation will have fixed frequency

Question 6

what forces are there in an atom

Answer 6

-strong nuclear force between proton and neutrons
-strongest atomic force
-can withstand repulsion between protons
- electrostatic force of attraction between electrons and protons

Question 7

how are cations and anions named

Answer 7

• cations–> metals –> metal+ ion
  -anions–> non metal–> -ide

Question 8

what did einstein discover about the mass of an atom

Answer 8

• small amount of mass is lost due to the strong nuclear force between neutrons and protons
• mass defect

Question 9

what is the definition of relative isotopic mass

Answer 9

the mass of an isotope relative to 1/12 th the mass of an atom of carbon-12

Question 10

what is the definition of relative atomic mass

Answer 10

• the weighted mean mass of an atom of an element relative to 1/12 th the mass of an atom of carbon 12

Question 11

how is relative atomic mass determined using a spectrometre

Answer 11

• sample placed in spectrometer
• sample vaporised then ionised to form cations
• ions are accelerated
• heavier ions move slower and are more difficult to deflect than lighter ions–> ions of each isotope are separated
• ions are detected on a mass spectrum as a mass-charge ratio (m/z)
  -each ion reaching the detector adds to the signal so the greater the abundance the larger the signal
  -the ratio is equivalent to the relative isotopic mass for cations

Question 12

what are binary compounds

Answer 12

• contains 2 elements only
• name of binary compound = first element + second element- ide