1.1 The atomic structure

Name the Matter around us

Solid , Liquid , gases

What was Empedocles belief

That 4 elements - the earth , fire , air , water made up all things

What was Democritus’s belief

That the material world has been made up of tiny , invisible , indivisible particles that they called “atomos “

What was meant by “atomos”

Indivisible/ uncuttable

What was Plato and Aristotle’s belief

That there can be no ultimately indivisible particles

What was the theory John Dalton put forward

Dalton's atomic theory

How many postulates did Dalton's atomic theory consist of ?

4

Name the 4 postulates of Dalton's atomic theory

1) Elements are made out of extremely small, indivisible particles called atoms

2) All atoms of a given element are identical in mass and size, but the atoms of one element are different from the atoms of all other elements.

3. Atoms of one element cannot be changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions.

4. Compounds are formed by union of two or more atoms of different elements in a simple numerical ratio.

Discovery of what proved each postulate of Dalton's atomic theory wrong ?

1) sub atomic particles were found

2) Discovery of isotopes

3) de to nuclea reactions

4) because of polymers

What was Dalton's atomic model called ?

Golf ball model

Who named the fundamental unit carrying electricity as electrons ?

Johnstone G.Stoney

Who invented the Crookes tube ?

William Crookes

What's the observation of crookes

When 2 electrodes are connected to a high - voltage source , the heated negatively charged plate ( cathode) produced a stream of invisible radiation ( the rays were not visible)

We're the rays emitted during Crookes experiment visible?

No

How did they detect the presence of rays

Because they cause gases at low pressure to glow and which madeother substances to flouresce or to give off light

What was the radiation emmoted from the cathode called ?

Cathode rays

Name 2 main features of cathode rays

Could be deflected by a magnetic field

Carried a negative electrical charge

J.J Thomson's observation regarding cathode rays

That cathode rays are same regardless of the identity of the cathode material or the gas in the tube

What did J.J thomson change in the cathode tube for his experiment

Used a cathode tube with an anode that had a hole at the centre

What did J.J . Thompson discover with his cathode ray tube

He was able to calculate the electrons electrical charge as 1.76×10⁸Cg–¹