Atomic structure and periodic tabler 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
What is the radius of the nucleus?
1 x 10 (to power of-14)
Is the nucleus positively or negatively charged?
Positively charged
Why is the nucleus positively charged?
Because of its protons.
Where is most of the mass of a Atom located?
Nucleus
What orbits the nucleus?
Electrons
Why do atoms have a neutral charge?
Because they have the same number of protons as electrons.
What is the relative mass of a Proton?
1
What is the relative mass of a Proton?
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
What is an Ion?
they are atoms with an overall charge . they have gained or lost electrons.
Do positive ions gain or lose electrons?
lose electrons
Do negative ions gain or lose electrons?
Gain electrons
What is the top the an element called?
Mass number
What is the bottom of an element called?
Atomic number
What does the mass number tell you?
The total number of protons and neutrons in the atom.
What does the atomic number tell you?
How many protons there are.
What is an element?
Is a substance with only one type of atom which has the same atomic number.
What are isotopes?
They are different forms of the same element which have the same number of protons but a different number of electrons .
Oxygen has a mass number of 16 and an atomic number of 8 with a charge of -2 what is the number of protons, neutrons and electrons?
8 protons
8 Neutrons
10 electrons
Aluminum has a mass number of 27 and an atomic number of 13 with a charge of +3 what is the number of protons, neutrons and electrons?
13 protons
14 neutrons
10 electrons
What is relative atomic mass?
it is the weighted mean mass of an element, taking into account all of the different isotopes and their relative abundance (amounts)
What is the formula to find the relative atomic mass of an element?
Relative atomic mass = Sum of (isotope abundance X isotope mass number/ sum of abundances of all the isotopes( 100)
Copper has two stable isotopes. Cu-63 has an abundance of 69.2 and Cu-65 has an abundance of 30.8%. Calculate the relative atomic mass of copper to 1 decimal place?
RAM = (69.2 X 63) + (30.8 + 65)/69.2 + 30.8
= 4359.6 + 2002/100
=6361.6/100 = 63.616
= 63.6
What is a compound?
Two or more elements which are chemically joined together in fixed proportions.
What is another key fact about compounds?
They usually have totally different properties to the elements that they are made from.
If we want to separate a compound back into its elements what do we need to do?
We need to use a chemical reaction to do this.
Making bonds involve what?
involves atoms giving away, Taking or sharing electrons. Only the electrons are involved ( the nuclei of the atoms aren’t affected at all when a bond is made)
What is a Molecule?
It has any elements chemically joined e.g. Ca(OH)2
What is a Formula?
It shows what atoms are in a compound in same proportions for example carbon dioxide is formed when 1 carbon atoms reacts with 2 oxygen atoms to give a compound of Carbon dioxide.
What is Formula for Carbon dioxide?
Co2
What is Formula for Ammonia?
NH3
What is Formula for Water ?
H20
What is Formula for Sodium Chloride?
NaCl
What is Formula for Carbon monoxide?
CO
What is Formula for Hydrochloric acid?
HCI
What is Formula for Calcium chloride?
CaCl2
What is formula for Calcium carbonate?
Na2CO3
What is formula for Sulfuric acid?
H(2)S04
If a formula e.g Ca (OH)2 has a two outside the bracket what does it mean?
The little number outside the bracket applies to everything in bracket so the formula Ca (OH)2 has 1 calcium atom, 2 oxygen atoms and 2 hydrogen atoms
Why are Mixtures easy to separate?
Because they are not like compounds they do not have chemical bonds.
What is a Mixture?
It consists of two or more elements or compounds not chemically bonded together, they are not in fixed proportions and the chemical properties are not affected being a mixture. (e.g a mixture of iron powder and sulfur powder will show the properties of both iron and sulfur. it will contain grey magnetic bits of iron and bright yellow bits of sulfur)
What is Chromatography?
Separating two or more dissolved solids from a solution.
What is the method of paper chromatography?
1) Draw a line near the bottom of a sheet of filter paper
(use a pencil because its insoluble(will not dissolve in solvent)
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) The solvent seeps up the paper, carrying the ink with it.
4)Watch each different dye in the pink separate out at different rates.
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 Filtration?
It separates insoluble(cannot dissolve in water) solids from liquids
What is the method of Filtration?
1) Set up apparatus with filter paper sitting in a concial flask
2) Pour insoluble solid and liquid mixture into the concial flask through the cone.
3) The liquid particles are small enough to fit through the filter paper but the solid particles are too big to pass through filter paper, so they are left behind.
4) the solid left behind is called residue and the liquid left behind is called the filtrate.
What is Evaporation
Separating soluble solids from solutions
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 Crystaliation?
Separating soluble solids from solutions
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 is Rock Salt?
It is a mixture of salt and sand. Salt and sand are both compounds but salt dissolves in water and sand doesn’t
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.
A student needs to produce pure crystals of copper sulfate from an aqueous solution of copper sulfate. Describe how the student could use crystallization for this process.
Pour the copper sulfate solution into an evaporating dish and slowly heat the solution until crystals form or some of the solvent has evaporated. Leave the dish to cool until crystals form. Filter and than dry the crystals using a dry oven
What is simple distillation?
Separates the solvent(the liquid that does the dissolving) from a solution.
What is the method for simple distillation (of saltwater)?
1) The solution is heated (the solution with the lowest boiling point heats first)
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 which is left in the water(pure water), leaving the salt behind.
How is simple distillation used in real life?
Purifying salty water to become drinkable
What is Fractional distillation used for?
To separate two or more liquids which have different boiling points.