C2 - The Periodic Table Flashcards
What is an alkali metal?
elements in Group 1 of the periodic table
What are halogens?
elements in Group 7 of the periodic table
What is a transition element?
elements form the central block of the periodic table
What is universal indicator?
a mixture of indicators that that can change colour through a range of colours to show how strongly acidic or alkaline liquids and solutions are
What are the noble gases
Elements in group 0
How are elements arranged in the periodic table?
Elements are arranged in vertical groups and horizontal periods
Why is it called the periodic table?
Because similar properties occur at regular intervals
What do elements in the same group have in common?
They have the same number of electrons in the valence shell and this gives them similar chemical properties
Elements that react to from positive ions (lose electrons) are…
Metals
alkali metals are ………… at room temperature
soft solids
alkali metals are extremely ……….
reactive
alkali metals have …….. densities
low
alkali metals have …….. melting and boiling points
low
alkali metals have melting and boiling points that ………. as you go down the group
decrease
alkali metals need to be kept in oil because………
They react with oxygen
reactivity ………. as you go down the alkali metals
increases
Why are alkali metals reactive?
they only have 1 electron in their outer shell and therefore only need to lose 1 electron to have a stable outer shell
density ……….. as you go down the alkali metals
increases
give the balanced chemical equation for Lithium reacting with Oxygen (lithium Oxide)
4Li(s) + O₂(g) -> 2Li₂O(s)
give the balanced chemical equation for Sodium reacting with Oxygen (Sodium Oxide)
4Na(s) + O₂(g) -> 2Na₂O(s)
give the balanced chemical equation for Potassium reacting with Oxygen (Potassium Oxide)
4K(s) + O₂(g) -> 2K₂O(s)
give the balanced chemical equation for Lithium reacting with Water (Lithium Hydroxide)
2Li(s) + 2H₂O(l) -> 2LiOH(aq) + H₂(g)
give the balanced chemical equation for Sodium reacting with Water (Sodium Hydroxide)
2Na(s) + 2H₂O(l) -> 2NaOH(aq) + H₂(g)
give the balanced chemical equation for Potassium reacting with Water (Potassium Hydroxide)
2K(s) + 2H₂O(l) -> 2KOH(aq) + H₂(g)
give the balanced chemical equation for Lithium reacting with Chlorine (Lithium Chloride)
2Li(s) + Cl₂(g) -> 2LiCl(s)
give the balanced chemical equation for Sodium reacting with Chlorine (Sodium Chloride)
2Na(s) + Cl₂(g) -> 2NaCl(s)
give the balanced chemical equation for Potassium reacting with Chlorine (Potassium Chloride)
2K(s) + Cl₂(g) -> 2KCl(s)
What does effervescence mean?
bubble/fizz
What are the observations of when Lithium reacts with water?
it floated on the water and effervescence releasing a gas, as it is an alkali it turned the universal indicator purple
What are the observations of when Sodium reacts with water?
it floated on the water and effervescence releasing a gas, as it is an alkali it turned the universal indicator purple
What are the observations of when Potassium reacts with water?
it floated on the water and burnt with a pink flame before exploding, as it is an alkali it turned the universal indicator purple
What are the observations of when Lithium reacts with oxygen?
Burns with a red flame to form a white powder
What are the observations of when Sodium reacts with oxygen?
Burns with a yellow/orange flame to form a white powder
What are the observations of when Potassium reacts with oxygen?
Burns with a lilac flame to form a white powder
what are some physical properties of group 7 elements?
poor conductors of heat and electricity, they are brittle and dull
melting and boiling points ………….. as you go down the halogens
increase
reactivity …………….. as you go down the halogens
decreases
Why does reactivity decrease going down the halogens?
Halogens gain electrons to from ions. As you go down the group the atomic radius increases and the electron shielding increases, this outweighs the increased nuclear charge, therefore the attraction of the nucleus on the electron it is gaining decreases making it harder to gain.
all halogens have … electrons in the valence shell
7
a more reactive halogen is able to displace a less reactive halogen from…
An aqueous solution of a halide compound
Why does reactivity increase going down the alkali metals?
Alkali metals lose electrons to from ions. As you go down the group the atomic radius increases and the electron shielding increases, therefore the attraction of the nucleus on the electron it is losing decreases making it easier to lose
Transition metals are good conductors of ……………………..
heat and electricity
Transition metals have ………. densities
high
Transition metals have …….. melting points
high
Transition metals are much ……. reactive than Alkali Metals
less
What colour are compounds of transition elements?
Brightly Coloured
What metals are often used as catalysts?
Transition metals
Transition elements form more than 1 type of ……..
ion
What is the balanced symbol equation for when chlorine water is added to an aqueous solution of potassium bromide?
Cl₂(aq) + 2KBr(aq) -> 2KCl (aq) + Br₂(aq)
What is the balanced symbol equation for when chlorine water is added to an aqueous solution of potassium Iodide?
Cl₂(aq) + 2KI(aq) -> 2KCl (aq) + I₂(aq)
What is the balanced symbol equation for when Bromine water is added to an aqueous solution of potassium Iodide?
Br₂(aq) + 2KI(aq) -> 2KBr (aq) + I₂(aq)
What are some observations of when chlorine water is added to an aqueous solution of potassium Bromide?
Changes from a colourless solution to a yellow solution
What are some observations of when chlorine water is added to an aqueous solution of potassium Iodide?
Changes from a colourless solution to a red-brown solution
What are some observations of when Bromine water is added to an aqueous solution of potassium Iodide?
Changes from a yellow solution to an orange solution
Why are noble gases not reactive
They have a full outer shell which makes them very stable.
What was John Newlands periodic table and when did he make it
John Newlands created his periodic table in 1864 and organised the elements in ascending relative atomic mass. He realised every 8 elements had similar properties so he started a new column every 8 elements so columns had similar properties. This worked up to calcium but then broke down so it was not accepted at the time.
What was Mendeleevs periodic table and when did he make it
Mendeleev created his periodic table in 1869. It was the same as Newlands except he left gaps where he expected undiscovered elements to go causing elements with similar properties to be in the same column. This did not always work and some elements had to be moved to fit their chemical properties.
What was Moseley’s periodic table and when did he make it
Moseley arranged the periodic table by proton number rather than relative atomic mass. This fixed the flaws in the periodic table. He also left gaps for undiscovered elements.
How does melting point change down the alkali metals?
Melting point decreases down the group
How does melting point change down the halogens?
Increases down the group
Describe the reaction between an alkali and a halogen:
- Vigorous reaction
* Produce a white solid