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Potassium has the most number of electron shells, meaning the valence shell is the furthest away from the nucleus. This causes the valence electron to be easily lost and for the potassium to react

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The reaction forms a layer of insoluble calcium sulfate around the metal which stops the reaction from continuing.

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An insoluble calcium sulfate layer forms around the metal thus disallowing for any chemical reaction to continue.

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The valence electron of potassium is the furthest away from the nucleus of potassium as compared to other alkali metals. Thus, the forces of attraction between the valence electron and the nucleus of potassium is weaker than the other alkali metals. As a result it is easier for potassium to lose that singular electron in the valence shell and hence it is the most reactive amongst the three alkali metals.

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When calcium reacts with sulfuric acid, calcium sulfate, an insoluble salt is formed. It forms a coat around the calcium which hinders the reaction between the calcium and the sulfuric acid. Hence, the reaction stops.

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The reaction will form calcium sulfate which is only sparingly soluble. This means that the calcium sulfate will form a layer around the calcium metal, preventing the calcium from reacting with the sulphuric acid and stopping the reaction.

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As the elements go down the group, it has more electron shells. This requires more energy to maintain, resulting in the valence electron experiencing decreasing amounts of attractive force from the nucleus, making it more likely to leave the atom to form ions. This results in group 1 metals being more reactive as the elements go down the group.

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A layer of insoluble calcium Sulfate forms on the metal, which prevents the metal from coming in contact with the acid, therefore no reaction occurs

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when calcium reacts with h2so4, a layer of insoluble salt calcium sukfate is formed, causing the rewction to stop

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The reaction between the calcium and the sulphuric acid forms an insoluble layer of calcium sulfate around the metal. Stopping the acid from reacting with the metal. Hence, the reaction stops after some time

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As the elements go down group I, the reactivity increases. Hence Potassium is the most reactive out of the three alkali metals. This is because, as you go down the row, the number of electrons increases. Therefore, the distance between the valence electron and the nucleus increases, decreasing the forces of attraction. This makes the one valence electron very easy to lose in a reaction to achieve noble gas configuration.

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The distance between the valence electrons and the nucleus increases due to the number of electron shells and radius of the valence shells, as it gets further from the nucleus/protons the forces of attraction becomes weaker as well. Due to the weaker forces of attraction, the amount of energy required overcome said forces decreases. Thus the melting points of the elements decreases as it increases the period.

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1) As we go down the column of group 1, the melting point decreases because of weak metallic bonding. As we go down the column, the ions gets larger and the distance between the electrons and nucleus increases, weakening force of attraction. Hence less energy is required to overcome the FOA and thus m.p is lower

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For element in group 7 , as elements go down from up to down , the number of electrons in atoms increases, increasing intermolecular forces of attraction between particles, larger amount of energy needed to overcome the forces of attraction. Hence melting and boiling point increases as elements move from up to down .     :D

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The melting point decreases down the group 1 as the ionic radii increases the attraction between the delocalised electrons and the attractive force of nuclei weakens.Hence,only a little amount of energy is required to overcome the electrostatic forces of attraction between the giant lattice of cations and a sea of delocalised electrons.

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As you go down the group , the forces of attraction become stronger between the atoms increase as the atoms become bigger and more energy is required to overcome the attraction , hence melting point will increase

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Group one metals are alkali they bare soft and can be cut easily. They have low melting points and the reactivity increases as you go down the table along the group

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As the period increases, the ions get larger therefore the distance between the bonding electrons and the positively charged nucleus gets larger, lowering the force of attraction. As there is less forces of attraction, less energy is required to overcome them when boiling or melting therefore the boiling point and melting point get lower as the period increases

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The melting point increases down Group VII as the number of atoms increase which causes an increase in the dispersion between the molecules. Hence, the melting point increases. For example, Fluorine has a melting point of -220 however at the bottom, astatine has a melting point of 301.8.

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Melting point decrease's down group I due to the increase in ionic radius. This increases the attraction between the delocalised electrons and the attractive forces at the nuclei weakens. Hence melting point decreases down group I.

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As you go down the periods, the elements increase in their number of subatomic particles. This results in increased molecule size, meaning the intermolecular forces increase in strength. Hence more energy is needed to partially overcome the intermolecular forces of attraction to melt the element.

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Because the further down a group the element is, the atoms become larger and the intermolecular forces of attraction become stronger. This means that it takes more energy to overcome these forces, resulting in a higher boiling and melting point.

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As the elements go down group 1, the distance between bonding(valence) electrons and the nucleus decreases. This decreases the forces of attraction between the molecules and hence decreases melting point.

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melting and boiling points increase as the number of electrons in the atoms increases, resulting in increased dispersion or London forces between the molecules.

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The melting point increases for halogens as the number of electrons in the atoms increase thus increasing the dispersion between atoms. ( London forces ) More energy is required to overcome the forces of attraction between atoms which increases their melting points.

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2. Why does melting point increase down the period?
- it increases as the number of electrons increase, meaning they have strong intermolecular forces between the molecules, thus more amounts of energy is required to overcome these forces and they therefore have a greater melting point and boiling point

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As the you go down the group 1 metals, metallic binding becomes weaker and thus it takes less energy to overcome forces of attraction. Thus, boiling and melting point decreases.

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As element go down from up to down, the ionic radius  decreases, which cause the attraction between nucleus and delocalised electrons to decreases, lesser amount of energy is needed to overcome the forces of attraction. Hence, the melting and boiling point decreases as elements move from up to down. :D

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1)Because of weak metallic bonds. Only one electron from each atom is delocalised and as the ionic radii increases the attraction between the delocalised electrons and the nuclei decreases.

2) it increases as number of electrons in the atoms increases, resulting in increased dispersion or London forces between the molecules

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As the elements go down the group , the element gets bigger and the valence electron gets further away from the centre which makes it easier to be lost. It requires lesser energy to be lost, hence melting point decreases because lesser energy is required and melting point is lower

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Q1. When a piece of metal, Calcium, is added to aqueous sulfuric acid, the reaction stopped after some time. Explain why.

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Q1. When a piece of metal, Calcium, is added to aqueous sulfuric acid, the reaction stopped after some time. Explain why.

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Q2. Using the trend in reactivity determined and the electronic structures, explain why potassium is the most reactive amongst the 3 alkali metals.

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Q2. Using the trend in reactivity determined and the electronic structures, explain why potassium is the most reactive amongst the 3 alkali metals.

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Q1. Why does the melting points decrease down Group I?

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Q1. Why does the melting points decrease down Group I?

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Q2. Why does the melting points increase down Group VII?

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Q2. Why does the melting points increase down Group VII?