Reactivity Trends (8)

2

Oxidation. 2 of their electrons are removed in order to have the same structure as the nearest noble gas.

They are reducing agents as they are oxidised and the 2 electrons removed from them will be accepted by another element which will become reduced.

They will react with oxygen to form metal oxides with the molecular formula MO as the +2 and -2 cancel out.

Reacts to make white magnesium oxide and burns with a bright white light. Mg is oxidised and O2 is reduced.

React to form a metal hydroxide M(OH)2 which is alkali because it releases OH- ions. Water reacts very slowly with the top elements, but as you go down the group it becomes more vigorous.

React really slowly because magnesium isn’t too reactive.

metal + acid -> salt + hydrogen

As you go down Group 2, the reactivity increases because of the first and second ionisation energies. It is a lot easier to remove the outer electrons on the lower elements due to electron shielding etc.. so the lower you go, the more reactive they are.

Makes the group 2 ion and 2 hydroxide ions which means it becomes an alkali solution. If the solution becomes saturated, the M2+ ion and 2OH- ion will combine to make M(OH)2 precipitate.

As you go down the group, the solubility of hydroxides in water will increase because the metals are more reactive so will be more attracted to the water and will result in more OH- ions being released.

The pH will increase as you go down group 2 as it is becoming more alkali as you go down. Magnesium is only slightly soluble in water so it will only release a few OH- ions, whereas Barium is more soluble so, will release a lot more OH- ions and have a bigger pH.

Used in agriculture or medicine

The use of Ca(OH2) which is white lime and neutralises acid in soil

Treats acid indigestion by neutralising it, and is called antacid. Neutralised the HCl in your stomach.

Add a spatula of metal oxide to a test tube and add water. Shake the tube and you won’t have enough water to dissolve all the metal oxide so you will have precipitate at the bottom and a solution which is your metal hydroxide. Test the pH of this to see what you get.

Group 7 elements that are the most reactive non-metal elements

As diatomic molecules with simple molecular structures. They exist in all states.

The boiling point will increase down the group and this is because they exist as diatomic molecules, so as you go down the group, the number of electrons increases, so the number of London forces increases. This means that the energy required to break the bond between them will get higher.

pale yellow gas

pale green gas

red-brown liquid

black solid

never been seen