Atomic structure and the Periodic table Flashcards
What is an atom?
Smallest part of an element that can exist.
What do atoms contain?
Atoms contain protons, neutrons and electrons.
What is the radius of an atom?
0.1 nanometres
What does the nucleus contain?
Protons and neutrons
Is the nucleus positively or negatively charged?
Positively charged
What orbits the nucleus?
Electrons
What is the relative mass of a Proton?
1
What is the relative mass of a Neutron?
1
What is the relative mass of an electron?
Very small
What is the charge of a proton?
+1
What is the charge of a Neutron?
0
What is the charge of an electron?
-1
Why do atoms have a neutral charge?
Because they have the same number of protons as electrons.
In an ion does the number of protons= the number of electrons?
No.
What is the top the an element called?
Mass number.
What is the bottom of an element called?
Atomic number.
What does the atomic number tell you?
How many protons there are.
What does the mass number tell you?
The total number of protons and neutrons in the atom.
What is an element?
Is a substance with only one type of atom which has the same atomic number.
What is an isotope?
Are atoms of an element with different numbers of neutrons.
What is relative atomic mass?
It is the average of the mass number of the different isotopes.
What does the abundance of an isotope mean?
How common each isotope is.
How do you calculate Relative atomic mass?
(mass number of isotope 1 x percent abundance of isotope 1) + (mass number of isotope 2 x percent abundance of isotope 2)/100
What is a compound?
Two or more elements which are chemically joined together in fixed proportions.
What is Filtration?
Separating an insoluble solid from a liquid.
What is Crystallization?
Separating a soluble solid from a liquid.
What is Simple distillation?
Separating a liquid from a dissolved solid.
What is Fractional distillation?
Separating two or more liquids which have different boiling points.
What is Chromatography?
Separating two or more dissolved solids from a solution.
What is the method of doing paper chromatography?
1) Draw a line near the bottom of a sheet of filter paper
(use a pencil because its soluble)
2)Add a spot of the ink on the line and place the sheet in a beaker of water or solvent.
3) Make sure ink isn’t touching the water
4)Watch each different dye in the pink separate out
5)When a solvent has nearly reached top of paper take it out the beaker wait for it to dry then the end result is a pattern of spots called chromatogram.
What is the method of getting pure dry salt from a solution? (Evaporation)
1) Pour the solution into an evaporating dish.
2) Slowly heat the solution, until crystals start to form as the solvent will evaporate.
3) Keep heating the evaporating dish until all you have left is dry crystals.
What is the method of getting pure dry salt from a solution? (Crystalization)
1) Solution is placed in a evaporating dish and is heated.
2) As solution is heated the water in solution is heated meaning less water.
3) Once water is evaporated crystals will appear, so remove dish from the Bunsen burner and leave it to cool.
What can filtration and crystallization be used for?
To separate rock salt
What is the method used to separate rock salt?
1) Grind mixture to make sure the salt crystals are small
2) Put measure in water and stir
3) Filter the mixture (sand wont fit through the tiny holes in filter paper so solid particles are left behind)
4) Evaporate the water from the salt so that it forms dry crystals.
What is the method for simple distillation?
1) The solution is heated
2) Water evaporates and its vapours rise. The water vapour passes into the condenser, where it cools and condenses, liquid water drips into the beaker.
3) All the water has evaporated from the salt solution, leaving the salt behind.
What is the method for Fractional distillation?
1) Put your mixture and stick a fractionating column o top and heat it.
2) Different liquids have different boiling points so they will evaporate at different temperature.
3) Liquid which has the lowest boiling points evaporates first
4) Liquids with higher boiling points might also start to evaporate
5) When the first liquid has been collected, you raise the temperature until the next one reaches the top.
What did John Dalton describe atoms in the early 19th century?
He described it at solid spheres and different spheres made up the different elements.
What did JJ Thompson discover in 1897?
The plum pudding model which showed the atom as a ball of positive charge with electrons stuck to it.
How did Ernest Rutherford disprove the Plum pudding model?
He conducted an experiment called the alpha particle scattering experiment, where he fired positively charged alpha particles at a extremely thin sheet of gold. The scientist expected the alpha particles to pass straight through, but some were deflected more than expected and a small number was deflected backwards.
What did Ernest Rutherford discover?
The nuclear model of an atom, where there is a tiny positively charged nucleus at the center, where there is most mass and a cloud of negative electrons surrounds it, therefore the atom is mostly made up with empty space.
What did Niels Bohr discovered?
Electrons orbit the nucleus in fixed shells and each shell is a fixed distance from the nucleus. Other scientists agreed.
What happened several years later the Nucleus Model?
The positive charge in the nucleus is due to tiny positive particles called protons.
What did James Chadwick discover 20 years later?
The nucleus also contains neutral particles called neutrons.
How did Mendeleev start to arrange the elements?
In order of atomic mass
What did Mendeleev do in 1869?
He took so known elements and arranging them into his table of elements with various gaps.
What was the first measure he took?
He put elements mainly in order of atomic mass but did switch the order if the properties meant it should be changed
What was the second measure he took?
He left gaps in the table to make sure elements with similar properties stayed in the same groups and also predicted the properties of undiscovered element based on other elements in the same group.
Describe two changes Mendeleev made to early periodic tables?
Left gaps and Predicted new elements.
Where are the metals formed on the modern periodic table?
Left
Where are non-metals found on the modern periodic table?
Right
What are vertical colums of the periodic table called?
Groups
What are the rows of the periodic table called?
Periods
What does the group number tell you?
How many electrons there are in the outer shell.
State 3 properties of Metals?
1) Strong
2) Great at conducting heat and electricity
3) Have high boiling and melting points
What are the properties of Group 1 metals?
Low density materials, very soft, low melting and boiling points and increasing reactivity.
What are Group 1 metals known as?
Alkaline metals
What happens when Group 1 elements react with metals?
They lose their one outer electron and form ionic compounds with a single positive charge which are generally white solids that dissolve in water to form colorless solution.
What happens when Group 1 metals react with water?
They produce Hydrogen gas
What products do lithium+water form?
Lithium hydroxide+hydrogen
What products do Sodium+water form?
Sodium hydroxide+hydrogen
What products do Potassium+water form?
Potassium hydroxide+hydrogen
Why are group 1 metals called alkaline metals?
Because Hydroxide dissolves in water to form alkaline solutions.
Why does Group 1 metals get more reactive as you go down the group?
It gets easier for the Group 1 metals to lose their outer electrons as you move down the Group
When Group 1 metals react with chlorine what do they form?
Salts
When lithium reacts with chlorine what does it produce ?
Lithium chloride
When Potassium reacts with chlorine what does it produce?
Potassium chloride
When Sodium reacts with chlorine what does it produce ?
Sodium chloride
When Group 1 metals react with oxygen what do they form?
Metal oxide
When lithium reacts with oxygen what does it form?
Lithium oxide
When Sodium reacts with oxygen what does it form?
Sodium oxide
When Potassium reacts with oxygen what does it form?
Potassium oxide
Are Group 7 elements metal or non-metals?
Non-metals
Group 7 elements form molecular with two atoms joined by what?
Molecular covalent compounds when they react with other non-metals.
What happens when Group 7 elements react with Metals?
They form ionic compounds when reacting with metal atoms, it gains one electron and forms a -1 ion which are called halides.
As we move more down Group 7 is the elements more or less reactive?
less reactive
Why as we move down group 7 why does the elements get less reactive?
Because as we move down the increase shielding and distances means that element gets less reactive.
What can more reactive halogens do to less reactive ones?
Displace it depending on trend in reactivity
What are the 3 trends as you go down Group 7?
1) less reactive
2) have high melting and boiling points
3) have higher relative masses
What are Group 0 elements known as?
Noble gases
What are the properties of noble gases?
Very unreactive and colorless gases at room temperature.
Why are Noble gases unreactive?
Because they have a full outer shell.
As you go down group 0 what is the trend with the boiling points?
The boiling points increases as the relative atomic masses increases
