C1 - Atomic Structure 1️⃣✅ Flashcards
What is an atom?
The smallest part of an element that can exist
What is the plum pudding model of the atom?
A sphere of positive charge with negative electrons embedded in it
Who invented the plum pudding model?
J J Thomson
What did scientists discover in the alpha scattering experiemnt?
(gold foil)
That some alpha particles were deflected by the gold foil this showed that an atom’s mass and positive charge must be concentrated in one small place (the nucleus)
Describe the nuclear model of the atom
Dense with electrons orbiting it
What did Niels Bohr discover?
That electrons orbit in fixed energy levels (shells)
What did James Chadwick discover?
An uncharged particle called the neutron
Where are protons and neutrons located in the atom?
The nucleus
What is the relative mass of each sub-atomic particle?
Proton - 1
Neutron - 1
Electron - 0 (very small)
What is the relative charge for each sub-atomic particle?
Proton - +1
Neutron - 0
Electron - -1
How can you find out the number of protons in an atom?
The atomic number on the periodic table
How can you work out the number of neutrons in an atom?
The mass number - the atomic number
Why do atoms have no overall charge?
Because there are equal numbers of positive protons and negative electrons
How many electrons can you have in the 1st, 2nd and 3rd shells?
1st shell - 2
2nd shell - 8
3rd shell - 8
What is an element?
A substance made up of one type of atom
What is a compound?
A substance made of more than one type of element chemically joined together
What is a mixture?
Two or more substances not chemically combined
What are isotopes?
Atoms with the same number or protons and electrons, but a different number of neutrons
What are the five physical processes that can be used to separate mixtures?
Filtration, crystallisation, chromatography, fractional distillation and simple distillation
What is relative atomic mass?
The average mass of all the atoms of an element
How do you work out the relative atomic mass of an isotope?
relative atomic mass = (abundance of isotope 1 x mass of isotope 1) + (abundance of isotope 2 + mass of isotope 2) OVER 100
What is the atomic number?
The number of protons in an atom
What is a molecule?
A molecule is a substance that contains two or more atoms
What is an ion?
Ions are completely stable elements e.g. when the amount of available shells are full of electrons
