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UK GCSE Level Chemistry Notes: The Group 1 Alkali Metals Li Na K etc.
Group 1 ALKALI METALS of the Periodic Table (re-edit) The physical and chemical properties of the Group I Alkali Metals of the Periodic Table and their compound uses These notes are written for the highest level of UK GCSE (~US grades 9-10), BUT, this page can act as a primer for the advanced level study of Group I alkali metals such as lithium, sodium and potassium. Sub-index for GCSE level page on Alkali Metals 2. General introduction to the Group 1 Alkali Metals 3. What are the important trends down Group 1 Alkali Metals 4. Selected data on the Group 1 Alkali Metals 5. The Reaction of Alkali Metals with cold water 6. Explaining the alkali metal reactivity trend 7. The Reaction of Alkali Metals with Non–metals 8. Some compounds of the alkali metals - formula patterns 9. Uses of alkali metals and their compounds 10. Comparison of Group 1 alkali metals and transition metals 11. The group 1 alkali metals in the context of the reactivity series of metals and implications 12. Learning objectives for UK GCSE level students (US grades 8-10) Alkali Metals GCSE/IGCSE level multiple choice QUIZ – harder Higher tier Alkali Metals GCSE/IGCSE level multiple choice QUIZ – easier Foundation tier See also Advanced A Level Chemistry Notes: s-block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals Keywords–Links for this revision notes page on alkali metals boiling points * chlorides * data on elements * density * electron arrangements explaining reactivity trend * hydroxides * melting points * oxides * reaction with oxygen/chlorine reaction with water * trends * typical properties * untypical properties * uses
1. Where are the Group 1 Alkali Metals in the Periodic Table? and the significance of their electronic structure
Electronic structure and reactivity of Group 1 Alkali Metals in the context of their position in the Periodic Table
These are typical electron changes for metals in groups 1, 2 and 3 and the alkali metals are on the furthest left of the periodic table with on one outer electron and it is on the left-hand side of the periodic table you find the most metallic character. Metallic elements on the left-hand side of the periodic table quite easily lose their few less strongly held outer electrons giving them a high reactivity in forming positive ions eg groups 1 and 2 readily lose 1 or 2 electrons respectively (as with Na and Mg above) to give an electronically stable noble gas structure with a full shell of outer electrons. These outer electrons, particularly for the alkali metals, are also shielded by other inner electron shells and farthest from the nucleus and so are less strongly held and need less energy to give positive ions with a full outer shell of electrons. Its energetically easier for an alkali metal to lose one electrons to form a stable positive ion than gain 7 electrons to form an unstable negative ion with a noble gas structure. Alkali metals have to lose the least electrons to form a stable positive ion with a noble gas structure, this requires the least energy and makes the group 1 alkali metals the most reactive metals on the left-hand side periodic table. These points and explanations are elaborated on by looking at the chemical reactions of alkali metals further down the page. |
TOP OF PAGE and sub-index for GCSE Alkali Metals page
See also Advanced A Level Chemistry Notes: s-block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals
2. General introduction to the Group 1 Alkali Metals (see also data table below)
Why are the group 1 alkali metals like lithium, sodium and potassium store under oil?
In what ways are the group 1 alkali metals like lithium, sodium and potassium typical metals?
In what ways are the group 1 alkali metals like lithium, sodium and potassium not typical metals?
TOP OF PAGE and sub-index for GCSE Alkali Metals page See also Advanced A Level Chemistry Notes: s-block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals 3. What are the important trends down Group 1 Alkali Metals
Alkali Metal flame colours
Revision notes on the physical and chemical properties of the group 1 alkali metals, chemical reactions of alkali metals, compounds of the alkali metals, explaining the reactivity trend of alkali metals, reactions with water, chlorine and oxygen, help when revising for AQA GCSE chemistry, Edexcel GCSE chemistry, OCR GCSE gateway science chemistry, OCR GCSE 21st century science chemistry GCSE 9-1 chemistry examinations. Parts or all of these notes are suitable for US grade 8 US grade 9 US grade 10 chemistry |
TOP OF PAGE and sub-index for GCSE Alkali Metals page
See also Advanced A Level Chemistry Notes: s-block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals
more advanced data | 4. Selected data on the Group 1 Alkali Metals | |||||
Chemical symbol, name of alkali metal |
Atomic number of alkali metal | Electron arrangement in shells 1, 2, 3 etc. of alkali metal | melting point oC, K of alkali metal | boiling point oC, K of alkali metal | Density g/cm3 of alkali metal | atomic radius in nm (nanometre) and pm (picometre) |
Li, lithium | 3 | 2.1 | 181oC, 454K | 1347oC, 1620K | 0.53 | 0.157, 157 |
Na, sodium | 11 | 2.8.1 | 98oC, 371K | 883oC, 1156K | 0.97 | 0.191, 191 |
K, potassium | 19 | 2.8.8.1 | 64oC, 337K | 774oC, 1047K | 0.86 | 0.235, 235 |
Rb, rubidium | 37 | 2.8.18.8.1 | 39oC, 312K | 688oC, 961K | 1.48 | 0.250, 250 |
Cs, caesium | 55 | 2.8.18.18.8.1 | 29oC, 302K | 679oC, 952K | 1.87 | 0.272, 272 |
Fr, francium | 87 | 2.8.18.32.18.8.1 | 27oC, 300K | 677oC, 950K | approx. 2 | ~0.280, ~280 |
GROUP 1 ALKALI METALS | Proton number of group 1 alkali metals | All group 1 alkali metals have one electron in the outer shell | The melting points of group 1 alkali metals decrease down the group. | Generally, the boiling points of group 1 alkali metals decrease down the group | Alkali metals have low densities, untypical of metals. |
Atomic radii increase down the group with each additional electron shell. |
Note: For atomic radii: 1nm = 10–9m, 1pm = 10–12m, nm x 1000 = pm, nm = pm/1000 Atomic radii always increase down a group with increase in atomic number because extra electron shells are successively added.
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TOP OF PAGE and sub-index for GCSE Alkali Metals page
See also Advanced A Level Chemistry Notes: s-block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals
5. The Reaction of Alkali Metals with cold water What is formed when group 1 alkali metals like lithium, sodium or potassium react with water? What do you see when the reaction takes place? Observations!
VIDEO of the reaction of group 1 alkali metals with water (from the UK's Royal Society of Chemistry)
Theoretically the alkali metal Francium is the most reactive alkali metal and therefore the most explosive metal when in contact with water, however, it is also very radioactive and so the experiment is highly unlikely to be performed!
Revision notes on the physical and chemical properties of the group 1 alkali metals, chemical reactions of alkali metals, compounds of the alkali metals, explaining the reactivity trend of alkali metals, reactions with water, chlorine and oxygen, help when revising for AQA GCSE chemistry, Edexcel GCSE chemistry, OCR GCSE gateway science chemistry, OCR GCSE 21st century science chemistry GCSE 9-1 chemistry examinations. Parts or all of these notes are suitable for US grade 8 US grade 9 US grade 10 chemistry |
TOP OF PAGE and sub-index for GCSE Alkali Metals page
See also Advanced A Level Chemistry Notes: s-block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals
6. Why are alkali metals so reactive? AND Why do Group 1 Alkali Metals get more reactive down the group with increase in atomic/proton number? How do we explain the group 1 alkali metal reactivity trend?
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Representations of the electronic changes that accompany the reaction of a group 1 alkali metal. The atom loses its outer electron to form a very stable ion with the electron configuration of a noble gas. ==> + e– Li or [2.1] ==> Li+ or [2]+ + e– ==> + e– Na or [2.8.1] ==> Na+ or [2.8]+ + e– ==> + e– K or [2.8.8.1] ==> K+ or [2.8.8]+ + e– |
Explaining the Reactivity Trend of the Group 1 Alkali Metals with water and acids
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TOP OF PAGE and sub-index for GCSE Alkali Metals page
See also Advanced A Level Chemistry Notes: s-block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals
7. The Reaction of Alkali Metals with Non–metals Group 1 Alkali Metals react with non–metallic elements to form colourless or white ionic compounds These compounds dissolve in water to give colourless solutions. For these reactions you can often substitute Li (lithium), K (potassium), Rb (rubidium), Cs (caesium/cesium) to obtain the equations for other Group I Alkali Metals. The reason why they are ionically bonded compounds is that alkali metals readily form positive ions e.g. for sodium ===> + e– Na or [2.8.1] ==> Na+ or [2.8]+ + e– AND non-metals like oxygen and chlorine also readily form negative ions. |
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Reaction of group 1 alkali metals with oxygen VIDEO illustrating the reaction of group 1 alkali metals with oxygen
What is formed when group 1 alkali metals like lithium, sodium or potassium react with oxygen (air)?
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Reaction with chlorine
and other halogens What is formed when group 1 alkali metals like lithium, sodium or potassium react with chlorine? VIDEO illustrating the reaction of group 1 alkali metals with chlorine
Since the charge on the group 1 metal ions is +1, and the charge on halide ions is -1, its easy to predict the formula of any ionic compound formed between an alkali metal and a halogen i.e. a 1 : 1 ratio.
Pd = period,
Gp = group
1H Note
that H does not readily fit into any group
Group 1 Alkali Metals and Group 7 Halogens So, you can deduce the
following table of all the possible ionic compounds formed from
the Group 1 Alkali Metals and the non-metal Group 7 Halogen
elements.
The matrix below shows you all the possible outcomes of the 1:1
ratio. |
TOP OF PAGE and sub-index for GCSE Alkali Metals page
See also Advanced A Level Notes: s–block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals
'normal molecular' and ionic formula, M = Li, Na, K etc. |
8. Some
compounds
of the alkali metals
-
more on formula patterns Alkali metals are so reactive in readily forming a singly charged positive ion, they usually form ionic compounds, they lose an electron and are NOT interested in sharing it to form a covalent bond! e.g. the formation of the ionic compound sodium chloride (see above) ONE atom combines with ONE atom to form Alkali metal compounds are usually white solids or colourless crystalline compounds. For more details see Details of the ionic bonding of sodium chloride NaCl |
hydroxides MOH, M+OH– |
The hydroxides are white ionic solids which very soluble in water to form strongly alkaline solutions (pH 13–14). See below for salt formation from hydroxides. |
oxides,
M2O
(M+)2O2– |
The oxides are white ionic solids, very soluble in water to form the metal hydroxide (see above). |
chlorides
MCl M+Cl– |
The chlorides are colourless crystalline solids. They soluble in water to give a neutral solution pH 7, universal indicator is green. They are typical ionic solids with high melting points due to the strong attractive forces between ions (ionic bonding details). This solution in water consists of sodium Na+ and chloride Cl– ions and can be electrolysed to make chlorine, hydrogen and sodium hydroxide. For more details see Electrolysis of sodium chloride solution (brine) Formed by neutralising the alkaline oxide or hydroxide with acids (more on Acids, Bases and Salts). e.g. word equation and symbol equations sodium hydroxide + hydrochloric acid ===> sodium chloride + water NaOH + HCl ===> NaCl + H2O NaOH(aq) + HCl(aq) ===> NaCl(aq) + H2O(l) (symbol equation with state symbols) |
nitrates
MNO3 M+NO3– |
Colourless, soluble, neutral crystalline salts, are formed by neutralising the alkaline oxide or hydroxide with nitric acid. e.g. word equation and symbol equations sodium hydroxide + nitric acid ===> sodium nitrate + water NaOH + HNO3 ===> NaNO3 + H2O NaOH(aq) + HNO3(aq) ===> NaNO3(aq) + H2O(l) (symbol equation with state symbols) |
sulfates
M2SO4 (M+)2SO42– |
Colourless, soluble, neutral crystalline salts, formed by neutralising the alkaline oxide or hydroxide with sulfuric acid. e.g. word equation and symbol equations sodium hydroxide + sulfuric acid ===> sodium sulfate + water 2NaOH + H2SO4 ==> Na2SO4 + 2H2O 2NaOH(aq) + H2SO4(aq) ==> Na2SO4(aq) + 2H2O(l) (symbol equation with state symbols) |
carbonates
M2CO3 (M+)2CO32– |
White, soluble, weakly alkaline solids formed by reacting the hydroxide with carbon dioxide gas e.g. the formation of sodium carbonate (+ water) e.g. word equation and symbol equations sodium hydroxide + carbon dioxide ===> sodium carbonate + water 2NaOH + CO2 ===> Na2CO3 + H2O 2NaOH(aq) + CO2(g) ===> Na2CO3(aq) + H2O(l) (symbol equation with state symbols) Alkali metal carbonates form salts with acids. e.g. sodium carbonate + hydrochloric acid ===> sodium chloride + water + carbon dioxide Na2CO3 + 2HCl ===> 2NaCl + H2O + CO2 Na2CO3(s) + 2HCl(aq) ===> 2NaCl(aq) + H2O(l) + CO2(g) (symbol equation with state symbols) (more details on pH, neutralisation, equations and salt preparations on "Acids, Bases and Salts") |
You will find more on theses sorts of equations on .... |
GCSE Level Notes on Acids, Bases, Salts and pH scale Equation Question on Acid reactions – word & symbol equations with answers supplied |
Other reactions involving alkali metals or alkali metal compounds |
When strongly heated the nitrates of sodium and potassium evolve oxygen gas (ignites glowing splint) and leaving a white residue of the nitrite salt i.e. sodium nitrate ===> sodium nitrite + oxygen (word equation) 2NaNO3 ===> 2NaNO2 + O2 2NaNO3(s) ===> 2NaNO2(s) + O2(g) (symbol equation with state symbols) and potassium nitrate ===> potassium nitrite + oxygen 2KNO3 ===> 2KNO2 + O2 2KNO3(s) ===> 2KNO2(s) + O2(g) (symbol equation with state symbols) |
TOP OF PAGE and sub-index for GCSE Alkali Metals page
See also Advanced A Level Chemistry Notes: s-block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals
9. Alkali Metals – Storylines – USES and .... | |||
sodium Na |
Used as a heat transfer coolant in certain nuclear reactors because of its excellent heat conduction properties. The energized vapour is an orange–yellow and used in street lamps. |
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sodium Na+ salts |
Common salt from sea water or underground deposits is sodium chloride, NaCl, and is the raw material for making sodium, hydrogen, chlorine and sodium chloride by electrolysis (see Group 7 Halogens notes). 'Soluble Aspirin' is the sodium salt of an organic acid. Salts of solid organic acids are usually more soluble than the acid itself. |
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Sodium hydrogen carbonate NaHCO3 |
Sodium hydrogencarbonate's old name is sodium bicarbonate, often referred to as 'bicarb', is used in baking soda, pharmaceutical products like indigestion tablets and fire extinguishers. |
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Sodium hydroxide NaOH |
An industrially important alkali used in the manufacture of soaps, detergents, salts of acids (see Aspirin above), paper and ceramics. |
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For more on uses of metals see Transition Metals and Extra notes on industrial chemistry GCSE/IGCSE notes 10. Comparison of Group 1 alkali metals and transition metals
11. The group 1 alkali metals in the context of the reactivity series of metals and implications for their extraction
12. Learning objectives for UK GCSE level students (US grades 8-10) BUT useful revision for higher level courses Advanced A Level Notes on Group 1 Alkali Metals Learning objective for the chemistry of the group 1 alkali metals (UK GCSE, IGCSE and US grade 9-10 level) Know where the alkali metals are in the periodic table - 1st vertical column. Know they are called the alkali metals because their reaction with water forms an alkali. Know the typical physical properties of alkali metals. Know the full electron structure of Li, Na and K, and know the rest of the alkali metals have one electron in the outer shell. Know that on reaction, alkali metals readily lose one electron to form a singly charged positive ion. Be able to argue why alkali metals readily lose electrons. Know the following important group trends down the group 1 alkali metals
Know alkali metals are stored under oil to reduce reaction with moisture and oxygen in the air. Know the alkali metals give characteristic flame colours that can be used as a simple identification test Be able to write word equations and balanced symbol equations for the reaction of alkali metals with water. Know the reaction between alkali metals and oxygen produces oxides that dissolve in water to form alkaline hydroxides. Know the reaction of alkali metals with halogens to form salt-like ionic compounds. Be able to describe, with electronic diagrams, the ionic bonding of the oxides and chlorides of alkali metals. Be able to predict the simple formulae of the compounds formed between alkali metals and halogens like chlorine. Know that the alkali metals hydroxides are neutralised by acids to form salts e.g. chlorides, sulfates and nitrates/ Be able to compare and contrast the relative properties of transition metals and alkali metals. Video summarising the reactions of group 1 alkali metals (from the UK Royal Society of Chemistry) used in GROUP 1 See also Advanced A Level Notes on s–block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals BUT this page can act as a primer for the study of alkali metals lithium, sodium, potassium etc. What next? Associated Pages GCSE Level (~US grades 8-10) School Chemistry Notes (students age ~14-16) Find your GCSE science course for more help links to revision notes Advanced Level (~US grades 11-12) pre-university Chemistry Notes (for aged ~17-18) Email doc brown - comment? query?
PLEASE NOTE that these LINKS are for Advanced A Level Chemistry Students ONLY ADVANCED LEVEL INORGANIC CHEMISTRY Part 7 s–block Gp 1 Alkali Metals/Gp 2 Alkaline Earth Metals sub–index: 7.1 Introduction to s–block Group 1 Alkali Metals and Group 2 Alkaline Earth Metals * 7.2 Group 1 data and graphs * 7.3 Group 2 data and graphs * 7.4 General trends down groups I & II and formulae *7.5 Oxygen reaction & oxides of s–block metals * 7.6 Water reaction & hydroxides of group 1/2 metals * 7.7 Acid reaction & salts of group1/2 metals * 7.8 chlorine reaction & halide of group I/II metals * 7.9 carbonates & hydrogen carbonates of s–block metals * 7.10 Solubility trends of groups 1/2 OH, NO3,SO4,CO3 compounds * 7.11 Thermal decomposition and stability of group 1 and group 2 carbonates & nitrates * 7.12 Uses of s–block Group 1 Alkali Metals and Group 2 Alkaline Earth Metals and their compounds See also Advanced Level Notes on s–block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals
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See also Advanced A Level Chemistry Notes: s-block Gp 1 Alkali Metals & Gp2 Alkaline Earth Metals