C1 - Atomic Structure Flashcards
The history of the periodic table
True or false: Dalton was the earliest contributor to the periodic table and published a list of elements
True
The history of the periodic table
What were Dobereiners triads?
Elements with similar chemical properties that were in groups of three
For example: lithium sodium and potassium due to similar reactions with water
The history of the periodic table
How did Newlands arrange the periodic table?
Arranged elements in and sort every eighth element reacts in a similar way
The history of the periodic table
What did Newlands call the fact that every eighth element in his table reacted the same way?
Law of Octaves
The history of the periodic table
True or false, both Newlands and Dobereiners collected, lithium, sodium, and potassium together
True
The history of the periodic table
What was the problem with the law of octaves?
 Some elements were grouped which had completely different properties (this was because they were ordered only increasing atomic weight)
The history of the periodic table
How did Dmitri Mendeleyev order the periodic table?
Give three things that he did correctly
He switched the order of elements to fit patterns of chemical properties already in the table.
He arranged elements in increasing atomic weight.
He also left gaps in the periodic table.
The history of the periodic table
Why did Dmitri Mendeleyev leave gaps in his periodic table?
He predicted the properties of elements in the gaps through their position on the table. This was good as these elements were later discovered to be correct by modern scientists. This is the main reason why his table is accepted today.
The history of the periodic table
What were the two problems with Dmitri Mendeleev’s periodic table
Protons had not been discovered yet, so he ordered elements by atomic weight, which meant due to the presence of isotopes he put some elements in the wrong order
he didn’t have noble gases.
The history of the periodic table
How do we arrange the periodic table now?
give three details
We arrange periodic table by increasing number of protons (atomic number).
We have groups.
We have periods.
Atoms
What is an atom?
The simplest form of matter in chemistry
Atoms
What three subatomic particles in an atom made of, and what are their charges masses and place in the atom
Proton neutron electron
+1, 0, -1
One, one, zero
Nucleus, nucleus, electron shells
Atoms
In what order are electron shells filled and how many electrons fill each shell?
Lowest to highest energy state
2, 8, 8
Atoms
What is a compound
A substance of two or more different elements, chemically bonded
Atoms
What is an element?
A pure substance made from one type of atom
Atoms
What does the group number represent in the periodic table?
The number of electrons in the outer shell
Atoms
Which way do groups go from top to bottom?
Up down
Atoms
What does the period number represent in the periodic table?
The number of electron shells
Atoms
True or false elements in the same period have similar chemical properties
True
Atoms
as you increase period number, what also increases
Reactivity
Atoms
Are periods, rows or columns
Rows
Atoms
What is the mass number represent in the periodic table
Protons, plus neutrons
Atoms
What is the atomic number represent in the periodic table?
Number of protons, all the number of electrons
Atoms
How many elements are there?
110
Atoms
Elements are arranged in increasing _____
Atomic number
Atoms
Do elements have an overall charge
No
Atoms
What is a mixture?
Two or more different substances not chemically bonded together that can be separated by physical process
History of the atomic model
Who is the author of the plum pudding model?
Thompson (1897)
History of the atomic model
What does the plum pudding model Describe?
A cloud of positive charge with negative electrons in embedded within
The negative electrons, the plums in the positive pudding
History of the atomic model
Did Thomsons model include the electron?
Yes
History of the atomic model
Did Thomsons model predict that the atom was solid?
No
History of the atomic model
Who was the author of the nuclear model?
Rutherford
History of the atomic model
What was Rutherford’s experiment in 1909?
He fired alpha particles at a very thin (a few atoms thick) piece of gold foil suspended in a vacuum
Some particles were deflected by large angles and some went straight through the foil and some were deflected 180 degrees
Deflection showed positive nucleus
Most straight through = mostly empty space
Small number coming straight back = centre of mass (nucleus) is in nucleus and the nucleus is very small!
History of the atomic model
What did Niels Bohr contribute to the model of the atom?
In 1915 he describes the fact that electrons orbit the nucleus at specific distances - in electron shells
History of the atomic model
Who discovered the modern nuclear model?
Chadwick in the 1920s
History of the atomic model
What did James Chadwick prove?
The existence of neutrons
History of the atomic model
What was the earliest of the atom and who authored it?
The bowling ball model, which proposed that the atom was a solid indivisible sphere
Dalton 1803
Isotopes
What is an isotope?
Atoms of the same element, but a different number of neutrons
Isotopes
What are the similarities and differences between two isotopes?
Proton/electron number/atomic number is the same
Number of neutrons is different
Remember in an exam always to give the number of neutrons in an isotope and name it using the full symbol (periodic symbol + mass number + atomic number)
Isotopes
What is relative atomic mass?
The average value that takes account of the abundance of isotopes of an element
Isotopes
How do you calculate relative atomic mass?
The sum of isotope abundances times isotopes mass number divided by the sum of the isotope abundances
Abundance is given as a percentage or ratio
Separating methods
What is distillation used for
Separating a mixture of two or more different liquids which have two or more different boiling points (fractional)
Of separating a liquid from a solution with a solid solute in it
Separating methods
What is the difference between fractional distillation and simple distillation?
Fractional distillation separates multiple (more than or equal to 2) different liquids with multiple (more than or equal to 2) different boiling points
Whereas simple distillation separate a solvent from a solute in a solution
Separating methods
Briefly describe the process of distillation
Heat, a mixture of solvents.
One will evaporate off into a Liebig condenser leaving behind the other solvent
This condenser cools the solvent and it drips into the conical flask
Separating methods
What is crystallisation?
The separation of a solute from a solvent to form crystals
Separating methods
Briefly describe the process of crystallisation
Evaporate the solution into a smaller volume and let it cool
As the solution cools crystals will form which can be obtained by filtration
Separating methods
What does filtration separate?
An insoluble solid from a liquid
Separating methods
Briefly describe the process of filtration
A mixture of solid and liquid or poured into the filter funnel and liquid drips through the filter paper, but solid particles are caught by the paper and separated
Separating methods
What does chromatography separate?
Mixtures of coloured compounds
Usually pen ink or food colouring agents
Separating methods
Briefly describe the process of chromatography
Spots of ink are placed on a pencil line. Paper is lowered into water below the pencil line and dye spreads up the paper.
Ink is separated into its colours forming a chromatogram.
Separating methods
What is a paper with separated chromatography inks called?
A chromatogram
Separating methods
The further up the paper a colour travels the more soluble/insoluble it is
Soluble
Separating methods
How could you increase the accuracy of a chromatography experiment?
 Put a lid on the beaker, prevent the liquid evaporating off
If it did not have a lid this would give the wrong RF value as the solvent wouldn’t travel high up enough the page
Separating methods
What is an RF value and how is it calculated?
It’s called the retardation factor
It is calculated by the distance, moved by the compound divided by the distance moved by the solvent
In this case, it’s the distance moved by the colour divided by the distance moved by water
Separating mixtures
What is a solution?
When is solute is dissolved in a solvent
Separating mixtures
What is a solvent?
A liquid substance, which may be mixed with a solute to make a solution
Separating mixtures
What does insoluble mean?
The solute can’t be dissolved in a solvent
Separating mixtures
What is a solute?
A solid substance which may be dissolved into the solvent to form a solution
Separating mixtures
What does soluble mean?
A solute that can dissolve with a solvent
Separating mixtures
What is a mixture?
Different substances, not chemically joined 
Why did Rutherford do his experiment in a vacuum?
So that any deflections were due to the gold foil and nothing else
Why was gold used by Rutherford in his experiments on the atom?
It was the only metal that could be rolled out very thin without cracking
Give all the diatomic elements and a way to remember them
Hydrogen
Nitrogen
Fluorine
Oxygen
Iodine
Chlorine
Bromine
Have no fear of ice cold beer!
True or false: elements in a compound are in fixed proportions
True
What is the chemical formula for magnesium oxide?
MgO
What is the chemical formula of sodium chloride
NaCl
What is the chemical formula of potassium bromide?
KBr
What is the formula for magnesium iodide?
MgI2
What is the formula for carbon monoxide?
CO
What is the Cornu,a for sulfur trioxide?
SO3
What is the formula for ammonia?
NH3
What is the formula for methane>
CH4
What is an ion?
A charged particle formed when an atom loses or gains electrons