P1+2 Flashcards
When was Daltons model discovered?
In the 1870s
When did dalton discover the atom
When doing an experiment to measure how elements combined
Describe Daltons model:
A small indestructible sphere
He thought that:
All atoms in an element are the same
The atoms in one element are different from atoms in all other elements
When was Thompson investigating cathode rays?
In 1897
What was the plum pudding model and when was it discovered?
It was discovered in 1904.
It suggests that the atom is a cloud of positive mass with negative electrons embedded in it
How does the history of the atom show that ideas change
The history of the model of the atom shows that ideas change when there is new evidence that cannot be explained using old ideas
What was Rutherford experiment?
In 1899 Rutherford discovered that some materials emit alpha particles and he decided to fire the alpha particles at a piece of gold foil
Describe Rutherford experiment
Alpha particle source in a lead box with a narrow hole
Fixed thin metal foil placed in front of the alpha source
The apparatus was placed in a vacuum chamber to prevent air molecules absorbing the alpha particles.
What was the Rutherford model of the atom?
an atom is made of a positively charged nucleus with electrons around the outside. Most the mass of an atom is in its nucleus
What is the Bohr model of an atom?
In 1913 Bohr suggested that electrons can only move in fixed orbits around electron shells
How do you find the length of a molecule
(Number of atoms) X 10^-10
What is density?
How much mass there is in a certain volume
How do you calculate density?
Density (kg/m3)= mass(kg) ➗ volume (m3)
What is temperature
Temperature tells you how cold something is.
Measured in Celsius or kelvin
What is specific heat capacity?
The heat required to raise the temperature if the unit mass of a given substance by a given amount
