group 2

    Master this deck with 43 terms through effective study methods.

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    Created by @jbf

    What's the flame colour for lithium

    Bright red

    What's the flame colour for sodium

    Bright yellow

    What's the flame colour for potassium

    Lilac

    What's the other name for group 2 elements

    Alkaline earth metals

    Why are group 2 metals more dense and have a higher melting point then group 1

    Have a smaller ionic radius and have2 delocalised electrons per ion and the 2+ ions are more strongly attracted to the electrons

    What happens to the ionic and atomic radii down the group 2

    Increase as there are more sub shells

    What happens to the first and second ionisation energy down the group

    It decreases because the outer s electrons get further from the nucleus as there are more sub shells and there is more shielding so the attraction between the nucleus and the electrons is weaker

    Why are group 2 ions smaller than any group 1 ion in the same period

    Group 2 ions have a higher positive charge of +2 instead of +1 and they are acting on 1 less electron. Therefore the effective nuclear charge is stronger between the nucleus and outer electrons so the attraction is stronger

    What kind of agents are group 2 metals

    Reducing agents

    What happens when group 2 metals react with oxygen apart from barium and strontium

    They burn in oxygen to form a white ionic oxide with M2+ ion sand 02-

    How can barium and Strontium react with oxygen

    Strontium and Barium can burn in excess air and excess temperature to form the peroxides Ba02 and St02

    What happens to the reactivity down group 2

    Increases because the outer electrons are lost more easily because the atomic radius increases and there is more shielding which outweighs the stronger nuclear charge

    Why do group 1 metals react with water more vigorously then group 2 metals

    As group 1 metals only have to remove on electron and their fist ionisation energy is less then the sum of the first and second ionisation energy on the group 2 metals. The atomic radius on the group 2 atoms is also smaller so it takes more energy

    What's the reactivity with water like down group 2

    Increases because the atoms lose electrons easier because the atomic radius is larger and there shielding is increased

    How does the solubility of group 2 hydroxides change down the group

    solubility increases

    What happens when magnesium reacts with cold water

    Forms magnesium hydroxide which is not very soluble and hydrogen

    What happens when magnesium reacts with steam

    Burns with a white flame and forms magnesium oxide (white powder) and hydrogen

    What happens to the products when calcium reacts with water

    Initially the calcium hydroxide dissolved but then becomes saturated and a white precipitate appears

    What happens to the products when barium reacts with water

    Barium reacts even faster and it's hydroxide is even more soluble

    What happens when group 2 metals react with chlorine

    All the metals form white chlorides which are all soluble

    What are the properties of the oxides of group 2

    They are white solids and are bases

    How is calcium hydroxide used

    It's slightly soluble in water forming an alkaline solution called limewater. This reacts with carbon dioxide to form calcium carbonate which is insoluble and white

    What does litihium carbonate and the group 2 carbonates thermally decompose to form

    the oxide and carbon dioxide

    what is the trend for thermal stability of group 2 carbonates/nitrates down the group

    They get more thermally stable down the group. The metal ions get less polarising so the bond between the carbonate/nitrate and the cation is stronger

    why is lithium carbonate able to thermally decompose

    it is small, so is charge dense enough

    what are the products when group 2 nitrates and lithium thermally decompose

    Form nitrogen dioxide an oxide and oxygen E.G. 2Mg(N03)2 -> 4N02 +2MgO + 02

    what are the products when group 1 nitrates apart from lithium thermally decompose

    Form a metal nitrite + oxygen E.g. 2Mg(N03)2 -> 2MgN02 + 02

    what's the flame test colour for beryllium

    no colour

    what's the flame test colour for magnesium

    no colour

    what's the flame test colour for calcium

    brick red

    what's the flame test colour for strontium

    red

    what's the flame test colour for barium

    pale green

    what's the flame test colour for copper

    green

    whats the trend in solubility of group 2 carbonates down the group

    they get less soluble

    what's the solubility of group 2 sulphates down the group

    they get less soluble

    what does nitrogen dioxide look like

    brown gas

    how is beryllium chloride different to other group 2 chlorides

    its covalent

    What happens when group 2 hydroxides react with acids.

    As the hydroxides are alkaline, this is a neutralisation reaction and forms a salt + water

    Why does beryllium not really react with oxygen

    because it forms a layer of beryllium oxide on the surface which stops any further oxygen from reacting

    What is the general formula for when a group 2 metal reacts with water

    react to form metal hydroxides and hydrogen. The metal hydroxide solution is alkaline which is why they are called alklali metals

    How do you carry out a flame test

    Take a nichrome wire and dip it in concentrated hydrochloric acid and then put it into a blue bunson burner flame. Repeat this cleaning until there is no coloured flames. Dip the wire into the metal and place into bunson burner

    Why are flame colours given off when metals are passed over a flame

    Electron exist in orbitals and when energy is supplied and absorbed by the metal, the electrons become excited and are promoted to a higher energy level. The electrons will drop back down to their original orbital they were in and this process releases energy, some in the form of light.

    Why do some metals produce no colour

    The colour depends on the wavelength of light. When some electrons drop down to their original orbitals, the energy emitted might not have a wavelength in the visible part of the electro-magnetic spectrum.