C1- Periodic Table, Structure of an Atom and Group 7 Flashcards
Where is the Nucleus of an atom?
In the middle
What is contained in the Nucleus?
Protons and Neutrons
Does the nucleus have a positive or negative charge, why?
Positive because of the protons
Where are the electrons of an atom found?
Around the nucleus in electron SHELLS
What is the relative charge of an electron and what is its mass?
- negative
- very small or 0
What is the relative charge of a proton and what is its mass?
- MUST say +1
- 1
What is the relative charge of a neutron and what is its mass?
- 0
- 1
Overall what charge does an atom have?
It is neutral
The number of…..is equal to the number of….
The number of protons is equal to the number of neutrons
What is the atomic number of Sodium?
23
Na
11
11
What does the atomic number tell you?
The number of protons there are .
So, how do you find the number of neutrons?
You subtract the atomic number from the relative mass.
So for sodium.. 23
Na
1 1
You do 23-11= 12 , there are 12 neutrons
What is an element?
An element is a substance made up of atoms, that all have the same number of protons in their nucleus.
What is an isotope?
Different forms of the same element, which have the same number of PROTONS but a different number of NEUTRONS
same atomic number different mass number for example Carbon-12 and Carbon-13
12 13
C C
6 6
What is the formula used to work out the relative atomic mass of an element?
sum of (isotope abundance x isotope mass number)
————————————————————————–
sum of abundances of all isotopes
What Is a compound?
Compounds are substances formed from two or more elements.
What are mixtures?
Two or more elements or compounds mixed together and are easily separated, unlike compounds.
What is chromatography?
Used to separate different dyes and ink. Separates compounds out of a mixture.
Names the steps of chromatography
1- Draw a line in pencil near the bottom of a sheet of filter paper. Pencil marks are insoluble and so won’t dissolve in the solvent.
2- Add a spot of the ink to the line and place the sheet in a beaker of solvent e.g. water.
3- The solvent used depends on what’s being tested. Some compounds dissolve in water, but sometimes other solvents like ethanol are needed.
4-Make sure the ink isn’t touching the solvent- you don’t want it to dissolve.
5-Place a lid on top of the beaker you don’t want the solvent evaporating
6- The solvent seeps up the paper carrying the ink with it.
7-Each different dye in the ink will move up the paper at a different rate so the dyes will separate out.
8- Any insoluble dyes in the ink will stay at the baseline
9-The end result is called a chromatogram.
What are filtration and crystallisation?
Methods of separating mixtures
If a solid can be dissolved, what is it described as being?
Soluble
Explain the method of evaporation.
1- Pour the solution into an evaporating dish.
2- Slowly heat the solution. The solvent will evaporate and the solution will become more concentrated. Eventually, crystals will begin to form.
3-Keep heating the evaporating dish until all you have left are dry crystals.
Explain the method of crystallisation.
1- Pour the solution into an evaporating dish and gently heat the solution. Some of the solvent will evaporate and the solution will become more concentrated
2- Once some of the solvent has evaporated or when you see crystals being formed, remove the dish from the heat and leave it to cool.
3- The salt should start to form crystals as it becomes insoluble in the cold, highly concentrated solution.
4- Filter the crystals out of the solution and leave them to dry .
What method could you use to separate rock salt?
1- Grind mixture to make sure salt crystals are small, so will easily dissolve.
2- Put the mixture in water and stir, the salt will dissolve but sand won’t
3- Filter the mixture. The grains of sand won’t fit through the paper. The salt passes through as it is part of the solution.
4- Evaporate the water from the salt to form dry crystals.
