Topic 1 - Atomic Structure and the Periodic Table Flashcards
Where is the nucleus in an atom?
In the middle of the atom
What is in the nucleus?
Protons and neutrons
What charge does the nucleus have?
A positive charge because of the protons
What is the relative charge of a proton, neutron and electron?
Proton - 1
Neutron - 0
Electron - -1
What is the relative mass of a proton, neutron and electron?
Proton - 1
Neutron - 1
Electron - 0
Where are the electrons in an atom?
They move around the nucleus in shells
What does an atoms nuclear symbol tell us?
The mass of the atom, the number of protons and the element symbol
What is a element?
An element is a substance made of atoms that all have the same number of protons.
What is an isotope?
An isotope is a element that has the same number of protons but a different number of neutrons.
How do you work out relative atomic mass?
Sum of (isotope abundance x mass number) / 100
What is a compound?
A compound is a substance of two or more chemical bonded elements in fixed proportions.
What is a mixture?
A mixture is two or more elements or compounds mixed together. They are not chemically bonded and can be separated using physical methods
What is chromatography?
Chromatography is the process of separating different dyes from an ink.
How can you do chromatography?
Draw a line near the bottom of filter paper - draw with pencil
Add spots of ink on the line and place the sheet in a solvent.
Place a lid on top to stop evaporation
The solvent seeps up the paper and carries the ink with it
What is filtration?
Filtration is the process of separating insoluble solids from a liquid.
How do you remove soluble solids from solutions?
Crystallisation.
What is simple distillation?
Simple distillation is the process of separating liquids from solution based of boiling point.
Who is John Dalton?
John Dalton described atoms as solid spheres in the 19th century
Who is JJ Thompson
Thomson concluded in 1897 that the spheres were positive with even smaller negative parts. He came up with the plum pudding model
What is the plum pudding model?
The plum pudding model states that an atom is a positive wall with negative electrons stuck in it
Who proved the plum pudding model is wrong?
Ernest Rutherford
Who is Ernest Rutherford?
He conducted the famous alpha scattering experiment.
What was the alpha particle scattering experiment?
An experiment that involved firing positively charged alpha particles at a thin sheet of gold.
What did the alpha particle scattering experiment involve?
It involves firing positively charged alpha particles at a thing sheet of gold
What three things were learnt from the alpha particle experiment?
Most of the atom is empty space.
There is a small, dense positively charged nucleus in the centre of an atom
There is a ‘cloud’ of negative electrons surrounding the nucleus
Who is Neils Bohr?
He made a nuclear model that suggested all electrons orbit the nucleus in fixed shells
Who is James Chadwick?
Chadwick carried out experiments which provided evidence for a neutral partial. This is now called a neutron
What are the three rules of electron shells?
The lowest energy levels are always filled first
The 1st shell can only hold 2 and the second and third only 8
If the outer shell is not full this makes the atom want to fill it
What was the periodic table like the in early 1800s?
In the early 1800s the periodic table was made of only known elements and was organised by atomic weight. These periodic tables were not complete and some elements were in the wrong group
Who is Mendeleev?
Mendeleev mainly put elements in order of atomic weight but changed some based on their properties. He also left gaps in the table where he predicted undiscovered atoms may fit the pattern - this was based off properties.
What is a metal?
A metal is an element that can form a positive ion
What are the properties of a metal?
They are strong, they are malleable and great at conducting heat and electricity.
What are three additional properties of transition metals?
They can form more than one ion
They are often coloured and firm coloured compounds
They often make food catalysts
