C1 - atomic structure and the periodic table Flashcards

Question

describe how the plum pudding model of the atom came about

Answer 1

at the start of the 19th century John Dalton described atoms as solid spheres and said the different spheres make up the different elements then in 1897 J-J Thompson concluded from his experiments that atoms were not solid spheres. His measurements of charge and mass showed that an atom must contain even smaller,negatively charged particles - electrons this new theory was known as the plum pudding model. it shows an atom as a ball of positive charge with electrons stuck in it

Answer 2

ernest rutherford

Answer 3

in 1909 ernest rutherford and his student conducted the famous alpha particles scattering experiment. They fired positively charged alpha particles at an extremely thin sheet of gold this meant that the plum pudding model couldn't be right so rutherford came up with the nuclear model of the atom

Answer 4

a tiny positively charged nucleus where most of the mass is concentrated a cloud of negative electrons surround the nucleus,so most of the atom is empty space

Answer 5

james chadwick

Answer 6

he put the elements in order of atomic weight he left gaps to make sure that elements with similar properties stayed in the same groups. some of the gaps indicated the existence of undiscovered elements and allowed mendeleev to predict what their properties might be. most of the predicted elements ended up being correct

Answer 7

- they are strong, but can be bent or hammered into different shapes - they are good conductors of heat and electricity - they have high boiling and melting points

Answer 8

non metals are more dull looking, they are more brittle and are not always solids at room temperature. they don't usually conduct electricity and often have a low density

Answer 9

-transition metals have more than one ion - they are often coloured and so compounds that contain them are colourful - they often make good cataylists.

Answer 10

- soft with a low density - the first three in the group are less dense than water - they all have one electron in their outer shell making them very reactive and they have similar properties

Answer 11

- the reactivity increases as you move down the group - the outer shell electron is more easily lost as the attraction between the nucleus and the electron decreases because the electron is further away from the nucleus the further down the group you go - lower melting and boiling points - higher relative atomic mass

Answer 12

- group one metals are much more reactive than transition metals - group one metals are also much less dense strong hard than the transition metals and have much lower melting points.

Answer 13

- they become less reactive as you move down the group because it is harder to gain an extra electron because the outer shell is further from the nucleus - they have higher melting and boiling points - they have higher relative atomic masses

Answer 14

displacement reactions can occur between a more reactive halogen and the salt of a less reactive one

Answer 15

- group 0 elements all have 8 electrons in their outer shell apart from helium which has 2 also giving it a full outer shell. because the outer shell is energetically stable they don't need to lose or gain any electrons. This means they are stable and don't react with very much -they exist as monatomic gasses - single gasses not bonded to each other. - all elements in group 0 are colourless gasses at room temperature - the noble gasses are non flammable

Answer 16

- the boiling points of the noble gasses increase as you move down the group along with increasing atomic mass - the increase in boiling point is due to an increase in the number of electrons in each atom leading to greater intermolecular forces between them which need to be overcome.