C1 Atomic Structure Flashcards
What are all substances made of?
Atoms
What is an element?
A substance that is made of only one type of atom
What is a compound?
A substance made of more than one element
What is the law of conservation of mass?
Total mass of reactants = total mass of products
What is a mixture?
Two or more substances that are not chemically combined together
Give three ways to separate mixtures
Filtration, crystallisation and distillation
What is filtration?
When you separate substances insoluble in a solvent from those that are soluble in the solvent. Like sand from salt
What is crystallisation?
When you separate a soluble solid from a solvent. Like salt from salt solution
What is distillation?
When you separate a solvent from soluble solids dissolved in the solvent. Like seawater distilled to obtain usable water
What is fractional distillation?
A way to separate mixtures of miscible liquids. Like water and ethanol
What does miscible mean?
When a liquid completely dissolves in another liquid
How does fractional distillation work?
The liquids have different boiling points and when the mixture is heated the liquid with the lower boiling is able to be collected first
What is paper chromatography?
A way to separate substances from mixtures in a solution
Why does paper chromatography work?
Because some compounds are more soluble than others in the solvent
What did Dalton suggest about atoms in the early 1800s?
That they were tiny hard spheres
What did Thomson discover at the end of the 1800s
A negatively charged particle called the electron
Who proposed the plum pudding model and what did it suggest?
It was proposed by Thomson and it suggested that negative electrons were embedded in a ball of positive charge
Who conducted the gold foil experiment and what did it prove?
It was conducted by Geiger and Marsden and it they proved that there was a tiny spot of positive charge in the centre of the atom by firing alpha particles at a thin piece of gold foil
Who proposed the nuclear model and what was it?
It was proposed by Rutherford and it was electrons orbiting around a nucleus which contained positively charged protons
What did Bohr suggest?
That electrons were orbiting the nucleus in energy levels
What did Chadwick prove the existence of?
Uncharged particles called neutrons in the nucleus
What are atoms made of?
Protons, neutrons and electrons
How do you find atomic number?
Number of protons (=number of electrons)
How do you find mass number?
Number of protons + number of neutrons
