Separate Chemistry - 5.1 Flashcards
What is the name of the smallest part of an element that makes up all substances?
An atom
What do all chemical symbols,
e.g. Na and O, have to start with?
A capital letter
Approximately how many different elements are there?
There are around 100 different elements.
What is a compound?
- Two or more elements
- Chemically combined
How can a compound be separated?
By a chemical reaction
What is a mixture?
Two or more elements, or compounds, that are not chemically bonded together.
What separation process is shown in the diagram?
Crystallisation
What type of separation process is shown in the diagram?
Filtration
What type of separation process is shown in the diagram?
Distillation
What type of separation process is shown in the diagram?
Fractional Distillation
What type of separation process is shown in the diagram?
Chromatography
Describe how you could use chromatography to identify a banned food dye in food colouring.
- Place food dyes on pencil line on chromatography paper.
- Place paper in solvent (e.g. water)
- The dye will dissolve in the water and spread up the paper.
- The colours in the dye will separate.
- Compare the patterns of the food dyes with the chromatogram of the banned food dye.
Why might a scientist decide to change or replace an existing model?
New experimental evidence is put forward
The discovery of what sub-atomic particle led to the plum pudding model of the atom?
The electron
Can you correctly label the diagram of the plum pudding model below?
Name the experiment shown in the picture
Alpha Particle Scattering Experiment
What two conclusions about the atom were drawn from the results of the alpha particle scattering experiment?
- The mass was concentrated at the centre (the nucleus)
- The nucleus was charged.
Who adapted the nuclear model of the atom by suggesting that electrons orbit at specific distances?
Niels Bohr
How many protons, electrons and neutrons are in the following elements?
*these are just examples, you need to be able to do this for any element by using your periodic table
Sodium (Na): 11 protons, 11 electrons, 12 neutrons
Nitrogen (N): 7 protons, 7 electrons, 7 neutrons
Fluorine (F): 9 protons, 9 electrons, 10 neutrons
Calculate the relative atomic mass of chlorine given the percentage abundances of the following isotopes of Chlorine:
75 % Chlorine-35 and 25% Chlorine-37
*this is just an example, you need to be able to do this for any element – you will be given the percentage abundances of isotopes
(75% x 35) + (25% x 37)
= 35.5
Write and Draw the electron structures of the following elements:
*these are just examples, you need to be able to do this for any of the first 20 elements by using your periodic table
Na: (2,8,1)
F: (2,7)
Why is the table of elements called a ‘Periodic Table’?
Because elements with similar properties occur at regular intervals.
Q. What are the columns in the Periodic Table called?
Q. What are the rows in the Periodic Table Called?
Q. How are the elements in the Periodic Table arranged?
- Groups
- Periods
- Atomic (proton) number
What similarities are there between elements in the same group?
- Same number of electrons in outer energy level/shell
- Similar Properties
What are the names of the sub-atomic particles in the nucleus of the atom?
Protons and Neutrons
Who discovered the neutron about 20 years after the discovery of the nucleus?
James Chadwick
What are the relative charges of the particles in an atom?
What are the relative masses of the particles in an atom?
Q. What is the charge on an atom?
Q. What relationship is there between the number of protons and electrons in an atom?
- There is no overall charge on atom
- The number of protons equals the number of electrons.
Q. What is the approximate size of the radius of an atom?
Q. Approximately how many times smaller is the radius of the nucleus of the atom?
- 0.1 nm (1 x 10-10 m)
- The radius of a nucleus is less than 1/10000 of that of the atom (ie over 10000 times smaller).
What is the definition of an isotope?
Atoms of the same element with a different number of neutrons.
Q. How do you calculate the mass number of an atom?
Q. What does the atomic number tell you about the particles in an atom?
- Mass number is the sum of protons and neutrons.
- Atomic number tells you the number of protons in an atom.
What does the Group Number tell you about the electrons in an element?
Group Number = Number of electrons in outer energy level / shell.
How were elements in the early periodic tables arranged?
By atomic weights
Who designed a Periodic Table that left gaps for undiscovered elements?
Mendeleev
What charge do non-metal ions (except Hydrogen) have?
Negative
What charge do metal ions have?
Positive
Q. Where are metals found on the Periodic Table?
Q. Where are the non-metals on the Periodic Table?
- Metals are on the Left-Hand Side of the Periodic Table
- Non-metals are on the Right-Hand Side of the Periodic Table
What are the elements in Group 0 called?
Noble Gases
In terms of electron arrangement, explain why noble gases are unreactive.
They have a full outer shell of electrons. (Helium has 2 electrons in outer shell, all other noble gases have 8 electrons in outer shell).
How does the boiling point of noble gases change as you go down the group?
It increases
What is the name given to the elements in Group 1 of the Periodic Table?
Alkali Metals
Name the products produced when sodium reacts with:
a) Chlorine
b) Oxygen
c) Water
*you will have to be able to do this for the first three alkali metals (lithium, sodium and potassium).
a )Sodium Chloride
b) Sodium Oxide
c) Sodium Hydroxide + Hydrogen
What happens the the reactivity of alkali metals as you go down the group?
Reactivity Increases
What are the elements in Group 7 of the Periodic Table called?
Halogens
Which group of elements form molecules made up of pairs of atoms?
The Halogens (Group 7)
Q. What happens to the melting and boiling points of Halogens as you go down the group?
Q. What happens to the reactivity of the Halogens as you go down the group?
- Melting and boiling points increase
- Reactivity decreases
Q. Name the type of reaction shown by the word equation below.
chlorine + sodium bromide → sodium chloride + bromine
Q. What does this reaction tell you about the reactivity of chlorine and bromine?
- Displacement Reaction
- Chlorine is more reactive than bromine (or vice versa)
Separate Q. What are the metals in the middle block of the periodic table called?
Transition Metals
Separate Q. Compare transition metals and alkali metals in terms of the following properties:
a )Strength
b) Hardness
c) Melting Points
d) Density
e) Reactivity
a) Transition metals are stronger (or vice versa)
b) Transition metals are harder (or vice versa)
c) Transition metals have higher melting points (or vice versa)
d) Transition metals have a higher density (or vice versa)
e) Transition metals are less reactive (or vice versa)
Separate Q. Name the metals that make useful catalysts.
Transition metals
Separate Q. Name the metals that make coloured compounds.
Transition Metals
Separate Q. Name the metals that can have ions with different charges.
Transition Metals
(e.g. an iron ion can be Fe2+ or Fe3+)
