Atomic Structure - Topic 1 Flashcards
What is the mass of a proton?
1
What is the mass of a neutron?
1
What is the charge on an electron?
-1
What is the charge on a neutron?
0
What is the mass of an electron?
Very small
What is the charge of a proton?
+1
Where in an atom are protons found?
Nucleus
Where in an atom are neutrons found?
Nucleus
Where in an atom are electrons found?
On shells
Define atomic number.
No. of protons in an atom
Define mass number.
Sum of protons and neutrons in an atom
How do you find out the number of electrons in an atom?
It is the atomic number (smaller number)
How do you find out the number of protons in an atom?
It is the atomic number (smaller number)
How do you find out the number of neutrons in an atom?
The mass number – the atomic number = the number of neutrons
How many electrons can you have on the first 4 shells of an atom?
2, 8, 8, 18
Define isotope.
Atoms of the same element that have the same number of protons but different numbers of neutrons
How do you calculate the relative atomic mass of an element?
Relative atomic mass = (isotope 1 mass × isotope 1 abundance + isotope 2 mass × isotope 2 abundance) ÷ total abundance
What is an ion?
A charged particle
How are positive ions formed?
An atom loses electrons
How are negative ions formed?
An atom gains an electron
What was the Dalton model of the atom?
Atoms = tiny spheres that cannot be divided
What did Dalton discover?
All atoms of an element are identical
What did Thomson discover?
· Atoms contain electrons
· Atoms are neutral overall
Describe Thompson’s ‘Plum Pudding’ model of an atom.
Ball of positive charge with electrons embedded throughout
Describe Rutherford’s model of the atom
Dense, positive mass in the centre (the nucleus) with electrons orbiting the nucleus.
What 3 things did Rutherford’s alpha scattering experiment prove?
1) Nucleus = positive (deflected & reflected +ve alpha particles)
2) Nucleus = dense mass in centre of atom
3) Rest = empty space
Describe the Neil’s Bohr model of the atom
Positive nucleus orbited by negative electrons
What did Bohr discover?
The electrons were in fixed shells around the nucleus
What did Chadwick discover?
The neutron
Describe Chadwick’s ‘Nuclear Model’ of an atom
Neutrons & protons in a +ve nucleus, -ve electrons in shells
What is the name for the current model of the atom?
Nuclear model
