Physical Abd Chemical Changes Flashcards
Chemical property
A substances ability to react with other substances to form new products
Chemical change
A change in nature of the starting materials undergoing a chemical reaction to produce one or more new substances difficult to reverse
Reactant
Starting materials is chemical reaction
Product
stuff that is made in chemical reaction
Reactant -> product ( which can be more than 1
5 signs of chemical reaction
Temperature change Colour change Odour produced Solid produced precipitate Gas or bubbles New substance formed
First elements were proposed by
Alchemists ( Europe)
First elements were
Air fire water earth
What was the alchemists purpose
To change metal / lead to gold
What is matter made of
Atoms
What are elements made of
Atoms
Atomic theory
All matter is made of small particles called atoms atoms can’t be created or destroyed or minimized same element same mass all element atoms mass differ compounds are created when atoms of different atoms link together in definite proportions
JJ Thomson
Discovered electrons and used a cathode to discover them used the plum pudding model
Ernest Ruth ford
Discovered protons used gold foil experiment to discover proton proposed nuclear model
Ruth fords conclusion I
The atom is mostly empty space with a solid positive center called a nucleus
Niels Bohr
Proposed electrons occupied energy levels called shells or orbitals