The reactivity series of metals
When Shiny element that is a good conductor of electricity and heat, and which forms basic oxides. react with other substances, the metal The smallest part of an element that can exist. lose Subatomic particle, with a negative charge and a negligible mass relative to protons and neutrons. to form positive Electrically charged particle, formed when an atom or molecule gains or loses electrons..
The A list of elements in order of their reactivity, usually from most reactive to least reactive. of metals is a chart showing metals in order of decreasing A measure of how vigorously a substance will react. The more reactive it is, the greater its reactivity and the more vigorous its reactions will be.. In general, the more The tendency of a substance to undergo a chemical reaction. a metal is:
- the more vigorous its reactions are
- the more easily it loses electrons in reactions to form positive ions (cations)
The table summarises some reactions of metals in the reactivity series. Hydrogen and carbon are shown for comparison.
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Reactions of metals with water
When a metal reacts with water, a metal hydroxide and hydrogen are formed. For example, sodium reacts rapidly with cold water:
Sodium + water 鈫 sodium hydroxide + hydrogen
2Na(s) + 2H2O(l) 鈫 2NaOH(aq) + H2(g)
In general, the more reactive the metal, the more rapid the reaction is.
Question
Describe and explain the observations when a small piece of lithium is placed on the surface of a big container of water. A few drops of universal indicator have been added to the water.
There is fizzing as the lithium reacts with the water to produce hydrogen gas. The colour of the universal indicator changes from green to purple as an alkaline solution of lithium hydroxide is produced.
Reactions of metals with dilute acids
When a metal reacts with a dilute Substance producing more hydrogen ions than hydroxide ions when dissolved in water. , a The substance formed when the hydrogen ion in an acid is replaced by a metal ion. and hydrogen are formed. For example, magnesium reacts rapidly with dilute hydrochloric acid:
Magnesium + hydrochloric acid 鈫 magnesium chloride + hydrogen
Mg(s) + 2HCl(aq) 鈫 MgCl2(aq) + H2(g)
The more reactive the metal, the more rapid the reaction is. A metal below hydrogen in the reactivity series will not react with dilute acids.
Question
Platinum is placed below gold in the reactivity series. Predict its reaction with dilute acids and explain your answer.
Platinum will not react with dilute acids. Metals below hydrogen in the reactivity series do not react with dilute acids, and both gold and platinum are placed below hydrogen.