C4 Flashcards
How is the Periodic table arranged?
Into groups and periods, in order of their proton number, this allows patterns to be found from their relative atomic masses and properties
What did Dobereiner discover?
He noticed ‘triads’ linking the RAM for three elements
What did Newlands discover?
He noticed ‘octaves’ where every eighth element had similar properties?
How did attitudes to early models of the periodic table develop?
At first Mendeleev’s table with gaps and predictions, Newlands’ triads and Dobreiner’s octaves were dismissed but when new elements were discovered that fit the patterns they were accepted
What are the group 1 metals and how do they react when cut?
Lithium, sodium, potassium are group 1 metals, when alkali metals are cut they are shiny at first then quickly tarnish in moist air due to reactions with oxygen.
What happens when alkali metals react with water?
They form hydrogen and an alkali solution of a hydroxide with the formula MOH
What happens when alkali metals react with chlorine?
They react vigorously to form colourless, crystalline salts withthe formula MCl
What trends are there in group 1 reactions with water?
As you go down the group they react with water more violently and vigorously
What are the main hazard symbols?
Highly flammable(big flame), toxic(skull and cross bones), corrosive (chemicals corroding), harmful(big x), explosive (explosion), oxidising(empty circle on fire)
What state and colour are halogens (group 7) at room temp and what colour as gases?
Chlorine is a pale green gas, bromine is a red-brown liquid and iodine a dark grey solid. As a gas chlorine is pale green, bromine reddish-brown, iodine purple
What is notable about all halogen molecules?
They are all diatomic, have 2 atoms joined together
What trends are there in group 7 in terms of reactivity?
As you go up the group they become more and more reactive
How does this reactivity affect their displacement of each other?
A displacement happens within a reaction when a more reactive (higher) halogen takes the place of a less reactive (lower) halogen.
How many electrons are in the outer shell of all group 1 metals?
1 electron in the outer shell, so form positive ions
How many electrons are in the outer shell of all group 7 metals?
7 electrons in the outer shell, so form negative ions
What safety precautions need to be taken when handling group 7s?
They are corrosive and toxic, they need to be kept in a fume cupboard when not in use
What are the state symbols and what do they mean?
(s) is for solids, (g) is for gases, (l) is for liquids and (aq) is for aqueous, when the substance is dissolved in a water solution.
How is an atom structured?
In the center is a very small nucleus containing protons and neutrons and then surrounding these are shells containing electrons
What is the relative charge and mass of each sub atomic particle?
Protons have a charge of +1 and a RAM of 1, neutrons have no charge and a RAM of 1, electrons have virtually no RAM and a charge of -1, all atoms have the same number of protons and electrons to balance their charge
What is a line spectrum and how does it relate to each element?
When heated elements emit a distinctive flame colour that can be put on a line spectrum to give a unique characteristic, these spectra can be studied to help discover what element it is and if its a new element.
How can we work out how many protons, neutrons and electrons an element has from the periodic table?
The proton number is the number of protons and so also the number of electrons, the RAM minus the proton number is the number of neutrons.
How do the electrons in the outer shell correlate across the periodic table?
Across a period, the number of electrons in the outer shell increases by 1, down a group the number of electrons in the outer shell is the same
Molten compounds of metals with non-metals conduct electricity, what is this evidence of?
That they are made up of charged particles called ions as when liquid they are free to move so the ions must move to the electrodes to complete the circuit and conduct electricity.
What is an ion?
An ion is an atom that has gained or lost an electron/electrons and so it has a complete outer shell and a positive or negative charge
What kind of compound is a compound of group 1 and group 7? What do they form?
An ionic compound is a compound of a non-metal and metal. They form crystals as they are arranged in a pattern called a regular lattice.
What happens to the ions when an ionic crystal melts or dissolves in water? and then what if an open circuit is put into the solution?
When dissolved in water the ions become free to move and so when a circuit is put in the solution the ions are able to move independently around the solution to complete the circuit as they are charged and able to freely morve
