Alkali metals Flashcards
Group 1 of the Periodic Table contains ……….
Lithium (Li)
Sodium (Na)
Potassium (K)
Rubidium (Rb)
Caesium (Cs)
Why do you think that the Group 1 metals are stored under oil?
A) To keep them moist and ready to react in experiments
B) To keep them out of contact with oxygen in the air
C) To lubricate the surface of the metal
B
The table below shows that Group 1 elements have low melting points for metals:
Group 1 metalMelting point (°C)
Lithium 180
Sodium 98
Potassium 63
Rubidium 39
Look at the table above. Which statement below is true?
A) There is no pattern in the melting points of the Group 1 metals as we go down the group.
B) The melting points of the Group 1 metals decrease as we go down the group.
C) The melting points of the Group 1 metals increase as we go down the group.
B
Predict the approximate melting point of caesium, the element below rubidium in Group 1.
Between 40 °C and 50 °C
Between 20 °C and 30 °C
Between 60 °C and 70 °C
B
Which Group 1 metal is most difficult to cut with a knife and has the highest melting point?
Sodium
Lithium
Potassium
Rubidium
Caesium
Lithium
Liquid sodium is piped around some nuclear power stations to transfer heat. Which two properties of sodium make it suitable for this use?
It has a low melting point.
It is a good conductor of heat.
Group 1 metals are called the alkali metals. why?
They get their name from their reaction with water, which produces an alkaline solution
Which of the alkali metals shown below ignites the hydrogen given off, which burns with a lilac flame?
Lithium
Potassium
Sodium
Which of the alkali metals shown below melts into a silver ball that moves around the surface of the water as it reacts?
Potassium
Sodium
Lithium
Sodium
You can collect the gas given off as lithium reacts with water. Which test shows that the gas collected is hydrogen?
A glowing splint re-lights
A lighted splint explodes with a squeaky ‘pop’
Limewater turns milky
A lighted splint explodes with a squeaky ‘pop’
What is the pH value of the solution produced when the Group 1 metals react with water?
7
Greater than 7
Less than 7
Greater than 7
Which of the three metals is most reactive with water?
Lithium
Potassium
Sodium
Potassium
Caesium explodes when put into water, smashing the glass trough. Which statement do you think describes the pattern in reactivity as we go down Group 1?
The Group 1 metals get less reactive as we go down the group.
The Group 1 metals get more reactive as we go down the group.
There is no pattern in their reactivity.
The Group 1 metals get more reactive as we go down the group.
Here are the equations for the reactions with water:
lithium + water lithium hydroxide + hydrogen 2 Li(s) + 2 H2O(l) 2 LiOH(aq) + H2(g)
sodium + water sodium hydroxide + hydrogen 2 Na(s) + 2 H2O(l) 2 NaOH(aq) + H2(g)
potassium + water potassium hydroxide + hydrogen 2 K(s) + 2 H2O(l) 2 KOH(aq) + H2(g)
What is the equations of the reaction between rubidium and water?
2 Rb(s) + 2 H2O(l) 2 RbOH(aq) + H2(g)
What is the equation of the reaction lithiumand water?
lithium + water lithium hydroxide + hydrogen 2 Li(s) + 2 H2O(l) 2 LiOH(aq) + H2(g)
What is the equation of the reaction sodium and water?
sodium + water sodium hydroxide + hydrogen 2 Na(s) + 2 H2O(l) 2 NaOH(aq) + H2(g)
What is the equation of the reaction potassium and water?
potassium + water potassium hydroxide + hydrogen 2 K(s) + 2 H2O(l) 2 KOH(aq) + H2(g)
Which of the equations below show possible reactions of lithium?
A) 4 Li(s) + O2(g) 2 Li2O(s)
B) Li(s) + Cl2(g) 2 LiCl2(s)
C) 2 Li(s) + Cl2(g) 2 LiCl(s)
D) Li(s) + O2(g) LiO2(s)
A & C
Write the equation showing the formation of potassium oxide is:
potassium + oxygen potassium oxide 4 K(s) + O2(g) 2 K2O(s)
The alkali metals react vigorously when heated with chlorine gas. Give an example:
sodium + chlorine sodium chloride 2 Na(s) + Cl2(g) 2 NaCl(s)
potassium + chlorine potassium chloride 2 K(s) + Cl2(g) 2 KCl(s)
Summary
Group 1 elements are called the alkali metals.
They are soft metals that tarnish quickly in air.
The Group 1 metals get more reactive as we go down the group.
Their melting points decrease as we go down the group. The melting points are all low for metals, as are the densities of these elements.
The alkali metals are the most reactive group of metals in the Periodic Table. They form soluble compounds that are usually white.
They react vigorously with water, giving off hydrogen gas and producing an alkaline solution.
Because they are very reactive, they are stored under oil.
Name the product of the reaction between potassium and chlorine.
Potassium chloride
Potassium oxide
Potassium chlorate
Potassium chloride
Predict the colour of the product in the previous question.
White
Caesium + water …
caesium hydroxide + hydrogen
As the atomic number of an alkali metal increases, its reactivity …
increases
Which gas is given off when an alkali metal reacts with water?
hydrogen
Which of these alkali metals is easiest to cut with a knife?
Lithium
Sodium
Potassium
Potassium
Which of the alkali metals has the highest melting point?
Lithium
Sodium
Potassium
Rubidium
Caesium
Lithium
what is the electronic structure for the below atoms
Sodium
Potassium
Lithium
Sodium 2,8,1
Potassium 2,8,8,1
Lithium 2,1
How many electrons are in the highest energy level (outer shell) of all the Group 1 metals?
1
What is the charge on the ion formed when an atom of an alkali metal reacts?
+1
Which of these would make it easier for an atom to lose an electron?
The electron being nearer to the positively charged nucleus
The electron being further from the positively charged nucleus
The electron being further from the positively charged nucleus
Why do the alkali metals get more reactive as we go down the group?
Because
This is because as we go down the group the outer electron of the atom is further from the attractive force of the nucleus. It is also shielded from the nucleus by more complete lower energy levels (full inner shells) of electrons.
If an electron is further from the attractive force of the nucleus, it is easier to remove it from the atom so it becomes more reactive
Why the alkali metals are the most reactive group of metals in the Periodic Table?
the atoms of alkali metals all have just one electron in their highest energy level (outer shell) and It is relatively easy to lose this one electron
losing this outer electron, they form stable ions with a 1+ charge, e.g. Na+.
As we go down Group 1,
The outer electron is more tightly held by the nucleus in larger atoms. True/False
The outer electron is further from the attractive force of the nucleus in larger atoms.
True/False
The outer electron is shielded from the attractive force of the nucleus by more inner shells of electrons. True/False
The outer electron in larger atoms is more strongly attracted by neighbouring atoms.
True/False
The outer electron is more tightly held by the nucleus in larger atoms. False
The outer electron is further from the attractive force of the nucleus in larger atoms.
True
The outer electron is shielded from the attractive force of the nucleus by more inner shells of electrons. True
The outer electron in larger atoms is more strongly attracted by neighbouring atoms.
False
Are these statements true or false?
- Metals are on the right of the periodic table.
- Metal hydroxide is made when metals react with air.
- Group 1 metals are kept under oil.
- Hydrogen is produced when group 1 metals react with water.
- Hydrogen is tested with limewater.
- Lithium is the most reactive group 1 metal.
- Metals are on the right of the periodic table. (F)
- Metal hydroxide is made when metals react with air. (F)
- Group 1 metals are kept under oil. (T)
- Hydrogen is produced when group 1 metals react with water. (T)
- Hydrogen is tested with limewater. (F)
- Lithium is the most reactive group 1 metal. (F)