īy the end of the reactions, all of the alkali metals dissolve in the water, producing metal hydroxides. It melts instantly as the potassium reacts so vigorously and quickly.Īs you can see from the reactions getting more vigorous, the reactivity increases as you go down group 1. The lilac colour comes from the potassium ions formed. The hydrogen gas produced ignites as potassium reacts so vigorously. The fizzing is from the hydrogen gas produced when lithium reacts with the water. Moves around the water, fizzing until it finally dissolves in the water Because they only need to lose 1 electron, it is very easy for an alkali metal to lose it to end up with a full outer shell, then becoming stable. This way, they are left only with the next outermost shell which is already full (remember electrons can only fill up the next shell if the previous one is completely full). For alkali metals which all have only 1 electron in their outer shell, the quickest way for them to obtain a full outer shell is by losing this 1 electron. That is their life goal! The way that atoms achieve this is by getting a full outer shell. In all reactions, all elements want to become stable. The way an atom of any element reacts depends on its electron configuration. They even react vigorously with water.Įlements in the same group have similar properties due to their electron configuration electrons are responsible for how an element reacts and what properties they have.Īll elements in group 1 have 1 electron in their outermost shell and as a result, they have similar properties. Very reactive, due to their electron configuration.When they react with substances to produce a compound, these compounds are white. As they are metals, they conduct heat and electricity very well. Good conductors of heat and electricity.The melting point for francium is only 27✬! The melting points and boiling points decrease as you go down the group. For metals, they have low melting and boiling points. The densities of the first three alkali metals (Li, Na, K) are all less than 1g/cm 3, making them less dense than water so they all float on water. However, they will become much more matte and dull in a short space of time as they react with the oxygen in the air, forming an oxide. They are shiny when you freshly cut them, you will notice that they are very shiny.They can all be cut with a knife, despite being metals!.Let's see some properties of the alkali metals: They are called alkali metals as when they react with water, they form an alkaline solution. However, you will most likely only encounter the first three in school as the others are far too reactive and therefore dangerous. Alkali metals: elementsĪlkali metals are lithium, sodium, potassium, rubidium, caesium, and francium. These noble gases are highly stable and do not react to form compounds under normal conditions.ģ) A column of elements in the periodic table.The alkali metals are all of the elements in group 1 of the periodic table. Elements Group 18 have a complete outer shell with eight electrons. They are also very reactive because they have seven electrons in the outer shell and will readily accept an electron in order to reach the ion configuration with the ideal number of eight electrons in the outer shell. They all have seven electrons in the outer orbital (two in level s and five in level p). They have only one electron in the outer shell (valence electron) and as a result are highly reactive. All elements in Group 1 for instance are alkali metals. Elements are arranged in these groups according to whose proprieties are similar. Because of the confusion the old IUPAC and the CAS system created, the IUPAC adopted their new system. This method, however, labeled columns 1 and 2 as 'IA' and 'IIA', columns 3 through 7 as 'IIIB' through 'VIB', column 8 through 10 as 'VIII', columns 11 and 12 as 'IB' and 'IIB' and columns 13 through 18 as 'IIIA' through 'VIIIA'. The CAS system, which also used Roman numerals followed by an 'A' or 'B'. Columns were numbed such that columns one through seven were numbered 'IA' through 'VIIA', columns 8 through 10 were labeled 'VIIIA', columns 11 through 17 were numbered 'IB' through 'VIIB' and column 18 was numbered 'VIII'. The old IUPAC system, which labeled columns with Roman numerals followed by either the letter 'A' or 'B'. To reduce confusion caused by the other two systems, this is the system that is used in articles on this web site. There are three common numbering systems for these groups: The new IUPAC system, which numbers each column with Arabic numbers from 1 (one) through 18 (eighteen). For more information see Periodic TablesĢ) The vertical columns (major classes or divisions) into which elements are arranged in the periodic table of elements. 1) A vertical column in the periodic table also called a family.
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