Atomic Structure Flashcards
What is the nucleus?
The middle of the atom containing protons and neutrons
it has a radius of 1 x 10^-14
it contains the majority of the mass of the atom
Protons
Positively Charged
Mass of +1
Equal to the number of electrons
Electrons
Negatively Charged
Mass of “very small”
Equal to the number of protons
Neutrons
Neutral Charge
Mass of 1
Varying Number of neutrons for each element (isotopes)
Why do atoms have a neutral charge
Protons have a charge of +1
Electrons have a charge of -1
There is an equal number of protons and neutrons so there therefore is no charge
What is an isotope
An element with the same number of protons and electrons but a varying number of neutrons
What is a compound
When two or more elements react and chemically bind together
They will react to form a neutrally charged compound
What is the Plum Pudding Model
Balls of positive charge with negative electrons randomly placed throughout
Who discovered electrons
JJ Thomson
Who created the Plum Pudding Model
JJ Thomson
What is the alpha scattering experiment
Alpha particles were fired at a sheet of gold metal
Conclusions from the alpha scattering experiment
Majority of the atoms mass must be concentrated at the centre
The centre must have a positive charge to repel the positive alpha particles
Majority of the atom must be empty space
What is the nuclear model
Positive nucleus with a cloud of negative electrons
Who discovered electrons orbiting the nucleus
Neils Bohr
Who discovered neutrons
James Chadwick
When were neutrons discovered
1932
When was the alpha scattering experiment
1909
What is the current model of the atom called
Bohr Model
What is the current model of the atom like?
Positive nucleus containing positive protons, neutral neutrons an negative electrons orbiting the nucleus
