Chemistry unit 1 Flashcards
What is an atom
The tiny particles that make up everything that exist
What is a compound
A chemical reaction takes place and it creates a compound which has 2 or more elements chemically bonded together in fixed positions eg HCl
What is a mixture
A substance made up of 2 or more elements that are not chemically bonded together. The substances in the mixture still have their own chemical properties
What is the charge on protons neutrons and electrons
Proton= +1
Election=-1
Neutron=0
What are the sizes of these particles
Proton=1
Neutron=1
Electron=1/2000
What is the atomic number on an element
How many protons are in the nucleus
What is the mass number on an element
The number of protons plus the number of neutrons
How many electrons can go in each shell of an atom
Shell 1 = 2
Shell 2 = 8
Shell 3 =8
Write out the electron configuration of sodium
(2,8,1)
Write out the electron configuration for oxygen
(2,6)
What is relative atomic mass
The average value that takes in the abundance of the isotopes of the element
What is an isotope
An element with the same number of protons and electrons but a different number of neutrons
What is an ion
An element that has lost or gained electrons in order to get a full outer shell and a charge
What did John dalton suggest about the atom
They were matter that could not be created destroyed of divided
They were the smallest thing that things were made up of. Atoms of the same substance were identical
What did J.J Thompson discover and how did this change the model of the atom
1897 J.J Thompson discovered the electron and proved that atoms could be divided into smaller particles.
Describe J.J Thomson’s Plum Pudding Model
A solid ball of positive charge with negative electrons scattered throughout
What experiment did Ernest Rutherford use to find the nucleus
Gold foil experiment- he shot an alpha ray at a thin gold foil and observed how it refracted
What were his results
Most rays went straight through so the atoms was mostly empty space. Some deflected at small angles showing that the centre of the atoms had a positive charge. Some deflected straight back showing most of the atoms mass was concentrated in the centre
How did Niels Bohr change Rutherfords nuclear atom model
He worked out that there were electron shells that stopped the positive nucleus and electrons collapsing and these shells were at set distances from the nucleus
What did James Chadwick discover
He discovered the neutron by accounting for the missing weight inside the nucleus and this furthered our understanding of isotopes
How do we order the periodic table
Groups: element that have similar properties are grouped together in columns
Periods: elements with the same amount of shells are in the same period. In general, elements are ordered by their atomic number
Who created the arrangement of the current periodic table
Dimitri Mendeleev
John Newlands law of octaves ?
He ordered his periodic table by atomic weight and this made it so every eighth element had similar properties but it was disproven due to its rigid structure
How was Mendeleev’s table different
He left gaps for elements that would be discovered in the future and when new elements were discovered, they fit in the gaps which helped to to prove his table correct
