F321 - The Periodic Table Flashcards
Why do the elements in a group have similar chemical properties?
They have similar outer shell electron configurations.
What does the term periodicity mean?
A repeating pattern of properties across different periods.
How did Mendeleev organise his periodic table?
By increasing atomic mass. He also arranged it according to repeating patterns of properties. He left spaces so that similar elements appeared in the same group. He then predicted what those elements’ properties would be.
How did Newlands arrange his periodic table?
In order of increasing atomic mass where the eighth element is a repetition of the first. His periodic table was arranged in octaves.
How did Dobereiner arrange his periodic table?
Arranged in triads where the middle of the three elements had an atomic mass that was a mean of the other two.
How did Moseley arrange his periodic table?
Increasing number of protons in the nuclei of atoms of the elements.
What is the periodic trend in ionisation energies?
Decrease down and group and increase across a period as nuclear charge increases across the period but electron shielding increases down a group.
Why is there a drop in ionisation energy between groups 2 and 3?
Change from s to p subshells.
Why is there a drop in ionisation energies between groups 5 and 6?
Starting to electron pair in the group 6 p orbital causing electron-pair repulsion.
What is the trend for atomic radii on the periodic table?
Increases down a group and decreases across a period as the number of electron shells increases down a group but the attraction of the nuclear charge to the electrons is greater across a group as they are in the same outmost shell.
How does the size of structures vary in the periodic table from left to right?
Giant metallic, giant molecular, simple molecular and individual atoms.
What are the products from the slow reaction of a group 2 metal with water?
Metal hydroxide and hydrogen
What are the products for a quick reaction of a group 2 metal and water?
Metal oxide and hydrogen.
What is produced from the reaction if a group 2 metal with oxygen?
Metal oxide
How does the reactivity of he element in group 2 vary?
Increasing reactivity down the group as it is easier to form cations (ionisation energies decrease) due to an increase in size, and electron shielding.
What is the pH of the solution formed from dissolving a group 2 metal oxide in water?
Weakly alkaline
Which type of reaction takes place when group 2 carbonates are heated?
Thermal decomposition
What is magnesium hydroxide used for?
Indigestion tablets to neutralise excess acid in the stomach.
What is calcium hydroxide used for?
Neutralise acidic soil to increase crop yield.
Why do the boiling points of group 7 elements decrease down the group?
Stronger van der Waals’ forces as you go down the group as there is an increased number of electrons.
What is the trend for reactivity down group 7? Why?
Decreases down the group. There is a decrease in the ease of making negative ions as the size of the atoms has increased meaning there is more shielding and less nuclear attraction.
What does the term disproportionation mean?
A type of redox reaction in which the same species is both reduced and oxidised.
How are halide ions tested for? What are the positive results?
Addition of silver nitrate and aqueous ammonia. Silver nitrate: Chloride - white precipitate Bromide - cream precipitate Iodide - yellow precipitate Ammonia: Chloride - dissolves in dilute Bromide - dissolves in concentrated Iodide - insoluble
What is chlorine used for in drinking water?
Kill bacteria
What are the disadvantages of using chlorine in drinking water?
Chlorine is highly toxic. It also reacts with traces if organic compounds in water which produce compounds that can cause cancer and act as mutagens.
