chemistry- atoms and elements chadwick and alpha esperiment

what is an atom made up of

protons, neutrons and electrons

why is an atom the smallest part of an element tha exists?

the atom is the smallest part of an element that still has all the properties of an element

what is an element

something made from atoms that all have the same number of protons.

what is a compound

2 or more elements that are chemically combined

give 1 difference between elements and compounds

1. elements cant be broken down chemically

compounds can

what is an ionic compound

metal and non metal elements chemically joined

what is a covalent compound

2 or more non metals chemically jooined

what is the law of conservation of mass

atoms cannot be created or destroyed, so the same atoms are rpesent befroe and after a reaction.

who discovered electrons

JJ thompson

who discovered protons

rutherford

who discovered neutrons

james chadwick

the work chadwick carreid out in his experiments allowed a better understanding of isotopes. how did his work make advances in out understanding of isotopes? ( 3 marks, 3 points)

- it proved the existence of neutrons

* and that isotopes have the same number of protons
* so isotopes are atoms of the same element, but with a different number of protons

the nuclear model of the atom was based on experimental work involving the alpha particle scattering experiment. the model replaced the old plum pudding model. compare the two models ( 4 marks, 4 points)

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1. the nuclear model has positive charge in the middle/ the plum pudding model has positive charge spread out
2. both models show the atom with negative charge
3. in the nuclear model, most of the atom is empty space/there’s no empty space in the plum model
4. both models show the atom with positive charge

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