ATOMS

Question 1

1803 john dalton

Answer 1

solid sphere model
atoms of the same element are identical
atoms of different elements are different

Question 2

1897 jj thomson

Answer 2

plum pudding
electrons from all elements were identical
negative electrons embedded in a positive cloud

Question 3

1909 ernest rutherford

Answer 3

nuclear model
fired alpha particles at thin gold foil
most passed through but a small fraction rebounded back
small positive nucleus surrounded by electrons

Question 4

1913 niels bohr

Answer 4

bohr model
electrons in fixed orbitals / shells
each shell has a fixed energy

Question 5

1926 erwin schrodinger

Answer 5

quantum model
‘you can never tell where an electron is or which direction its going’
complicated equations calculate the most likely places where an electron might be found

Question 6

what is atomic number

Answer 6

number of protons in the nucleus

Question 7

what is mass number

Answer 7

total number of protons and neutrons in the nucleus

Question 8

what are isotopes

Answer 8

atoms with the same number of protons but a different number of neutrons
same chemical properties as they have the same electronic configuration
different physical properties as their masses are different