Unit 1.6 - The Periodic Table Flashcards
What do elements in the same group have?
The same number of electrons in the outer shell
Which elements have the same number of electrons in the outer shell?
Elements in the same group
What do elements in the same group form?
Compounds with similar formulae and properties
How does the atomic radius change when going down the groups and why?
There’s an increase in the number of filled shell which leads to an increase in atomic radius
What causes an atomic radius to increase?
The number of filled shells
What’s the difference between the different atomic radius’ of different elements?
A difference of nm’s
Which element has the largest atomic radius?
Caesium
Which properties change whilst going down the groups in the periodic table?
-Atomic radius
-First ionisation energy
-Melting points
-Electrongativity
What happens to the first ionisation energy of elements a you move down the groups and why?
Decreases, as the outer electron has a larger amount of screening and distance from the nucleus, which outweighs the fact that it has an increased nuclear charge, meaning that there’s less energy required to remove electrons from the atom, so there’s a decrease in 1st ionisation energy
What happens to the melting points of different elements as you move down the groups?
It’s not possible to make a definitive statement about the variation of melting points down a group - each group must be studied individually
What’s the trend in terms of melting point down group 1?
Melting points decrease
What’s the trend in terms of melting points in group 2?
No definite trend
What’s the trend in terms of melting point in group 7?
Melting points increase down a group
What happens to a reaction occurring with elements from group 1 moving down the group?
React more vigorously
Which group elements react vigorously with chlorine?
Group 1
What do group 1 elements react vigorously with?
Chlorine
Why do elements react more vigorously as you move down group 1?
-Larger atoms
-Attraction between electron and nucleus is weaker as they’re further away, so it’s easily lost
What do the fact that the atoms are bigger and that the attraction between the electrons and nuclei are weaker mean for the elements moving down group 1?
They react more vigorously
Electronegativity definition
The ability of an atom to attract a pair of electrons to itself in a covalent bond
The ability of an atom to attract a pair of electrons to itself in a covalent bond
Electronegativity
What happens to the Electronegativity of elements as you move down a group and why?
Decreases due to increased screening
What happens to the Electronegativity of elements as you move across the periods and why?
Increases (UP TO GROUP 7) due to increased nuclear charge
What similar method of thinking for the explanations can we use when describing Electronegativity?
Ionisation energy
(E.g - references to shielding and nuclear charge)
In which direction on the periodic table does the Electronegativity value of elements decrease? Why?
Down a group
Increasing shielding
In which direction on the periodic table does the Electronegativity value of elements increase? Why?
Across a period
Increasing nuclear charge
Describe the Electronegativity values of metals
Low
Describe the electronegativity values of non-metals
High
Which type of elements have low electronegativity values?
Metals
Which type of elements have high electronegativity values?
Non-metals
What are the three most electronegative elements (in order from most to least)
F (most)
O
N
What is the most electronegative element?
F
What is electronegativity measured using?
A Pauling scale
What does a Pauling scale measure?
Electronegativity
What’s the significance of the difference in electronegativity between 2 atoms?
The larger the difference in electronegativity between 2 atoms, the more polar the covalent bond
What makes a covalent bond between two atoms more polar?
A larger difference in electronegativity between 2 atoms
What does an even higher difference in electronegativity between 2 atoms do?
Creates an ionic bond
When is an ionic bond present between 2 atoms?
When they have a particularly large (larger than a polar covalent bond) difference in electronegativity
What type of bond is in water?
Polar covalent bond
What does δ represent in water?
A partial charge (less than associated with ions)
What os used to represent a partial charge in water?
δ
What happens to the electrons in a compound (taking electronegativity into consideration)?
The bonding electrons are pulled towards the more electronegative element
Which element are electrons pulled towards in a compound?
The more electronegative element
What does the most electronegative element do within a compound?
Pulls the bonding electrons towards it
What makes the bond polar in water?
The bonding electrons are pulled towards the more electronegative element (oxygen, in the case of water)
Which is the most electronegative element in water?
Oxygen
List 4 properties that increase down a group
-Metallic character
-reducing power
-Ionic character of compounds
-Basic character of oxides
What is the trend for the following properties - Metallic character, reducing power, Ionic character of compounds and Basic character of oxides?
All increase down a group
List 3 properties that decrease down a group?
-Electronegativity
-Non-metallic character
-Oxidising power
What is the trend for the following properties - Electronegativity, Non-metallic character and Oxidising power?
All decrease down the group
What’s the name for elements that have properties intermediate between a metal and a non-metal?
Metaloids
Metaloids
Have properties intermediate between a metal and a non-metal
Give 2 examples of Metaloids and why you say this
Al and Si as they’re on the barrier between metals and non-metals on the periodic table
Which gases exist monoatomically?
Noble gases (group 0)
What do the noble gases exist as?
Monoatomic gases
Which group on the periodic table are the noble gases?
Group 0
What are on group 0 on the periodic table?
Noble gases
Which gas exists s a diatomic gas with a triple bond between two atoms?
Nitrogen
What does the fact that nitrogen has a triple bond between 2 atoms make it?
Unreactive
Why it nitrogen unreactive?
It has a triple bond between 2 atoms
What are some elements that can form acidic oxides when reacted with 02?
P, C, Cl and S
What do P, C, Cl and S do when reacted with 02?
Form acidic oxides
What type of metals are those in group 1?
Alkali metals
Where are the alkali metals on the periodic table?
Group 1
Which elements on the periodic table have giant molecular structures?
C and Si
What type of structures do C and Si have?
Giant molecular structures
What are the two most common elements
Oxygen then silicon
What’s the most common metal?
Aluminium
Describe P and S
-single molecular structures
-solid at room temperature
What does Na do (3 things)?
-floats on water
-melts
-reacts vigorously with water
Give an example of an element that floats on water
Na
Give an example of an element that reacts vigorously with water
Na
Oxidation
Loss of electrons
Reduction
Gain of electrons
Phrase for when an element loses electrons
Oxidation
Phrase for when an element gains electrons
Reduction
How can we tell when an element has been oxidised?
Increase in positive charge
How can we tell when an element has been reduced?
Decrease in positive charge
What’s the name for an ion that reduces?
Reducing agent
Reducing agent
Ion that reduces
What’s the name for an ion that oxidises?
Oxidising agent
Oxidising agent
Ion that oxidises
What happens to a reducing agent in a redox reaction?
Oxidised
What happens to an oxidising agent in a redox reaction?
Is reduced
Under which conditions are reducing agents oxidised and oxidising agents reduced?
In a redox reaction
Name 4 common oxidising agents
Oxygen
Chlorine
Bromine
Potassium manganite (VII)
What are oxygen, chlorine, bromine and potassium manganate (VII) all examples of?
Common oxidising agents
Name 4 common reducing agents
Hydrogen
Carbon
Carbon monoxide
Metals
What are hydrogen, carbon, carbon monoxide and metals all examples of?
Common reducing agents
Name 4 reactions that are NOT redox reactions
- Precipitation reactions
- Acid-base reactions
- Acid-carbonate reactions
- Thermal decomposition reactions
What are the following - precipitation reactions, acid-carbonate reactions, acid-base reactions and thermal decomposition reactions?
NOT redox reactions
What concept does using oxidation states use?
All compounds are ionic compounds, where every element has a specific oxidation state
Definition of oxidation state
The formal charge on the atom in a compound after the removal of the bonding electrons
What happens to the oxidation state of an element if it’s undergone oxidation?
Increase in oxidation state
What happens to the oxidation state of an element if it’s undergone reduction?
Decrease in oxidation state
What causes an increase in an element’s oxidation state?
Oxidation
What causes a decrease in an element’s oxidation state?
Reduction
What is the rule with increasing and decreasing oxidation states?
The sum of the increase in oxidation state must equal the sum of the decrease in oxidation state
What are carbon and carbon monoxide used in and why?
As reducing agents in the blast furnace
Which elements are used as reducing agents in the blast furnace?
Carbon and carbon monoxide
What’s the name for the group 1 metals?
Alkali metals
Where are the alkali metal on the periodic table?
Group 1
What are the group 2 elements?
Alkaline Earth metals
Alkaline Earth metals
Group 2 metals
What are the group 1 metals?
Li —> Cs (not Fr)
What are the group 2 metals?
Be —> Ba (not Ra)
Describe the electronic structure of group 1 metals
One electron in their outer shell - the s orbital is being filled = very reactive metals which form ionic compounds
Describe the electronic structure of group 2 metals
Two electrons in the outer shell - the s orbital is full
What do both group 1 and 2 metals form?
Ionic compounds
What form ionic compounds?
Group 1 and 2 metals (except Beryllium)
Which metals are the most reactive - group 1 or 2 ?
Group 1
What does Beryllium not do like the other group 1 and 2 metals?
Form ionic compounds
Which elements in the group 1 and 2 metals does not form ionic compounds?
Beryllium
Describe the difference in ionisation energy when moving across the period from group 1 to 2
Increase in nuclear charge with the same amount of screening and distance from the nucleus = more energy needed to remove one electron from an atom in group 2 = increase in ionisation energy
Which elements have the highest amount of ionisation energy - group 1 or 2 and why?
2 as there’s a higher nuclear charge whilst screening and distance from the nucleus remains constant = more energy required to remove an electron from an atom in group 2 = increase in ionisation energy
Describe the structures of the elements in group 1
Cubic
Which elements have a cubic structure?
Group 1
Describe and explain the melting points of group 1 elements upon moving down the group
The atoms get larger
The force of attraction between the atoms decrease
The energy required to melt the elements decreases
= low melting points (odd for a metal)
Do group 1 elements have low or high melting points?
Low (which is odd for a metal)
Why do the melting points of group 1 metals decrease down the group?
Atoms getting larger
Force of attraction between the atoms decreases
Energy required to melt the elements decreases
What happens to the reducing power of the elements on going down the group?
Increases
What does the fact that the reducing power of the elements increases upon going down the group mean?
The elements show an increased tendency to form ions (cations)
Word for elements showing an increased tendency to form ions
Reducing power
Describe the reactivity of elements upon doing down the group and explain this
Increases as it’s easier for a metal to lose an electron
What does the fact that it’s easier for metals to lose an electron upon going down the group make it?
More reactive
What happens to the reactivity of elements upon moving down the groups?
Increases
What happens to the reducing power of elements on moving down the groups?
Increases
In what type of reactions does the reducing power and reactivity of elements going down a group increase?
Redox reactions
Group 1 elements reactivity with water upon going down the group
Increases down the group
How do group 1 elements react with water?
Vigorously
What do group 1 elements do when reacted with water?
Float and move around on the surface before eventually dissolving
Which metals react most vigorously in water? (Group 1 or 2)
Group 1
Elements of which group float and move around on the surface of water before eventually dissolving when reacted with it?
Group 1
What is formed when a group 1 element reacts with water?
Hydrogen gas and an alkaline solution
When is hydrogen gas and an alkali solution created?
When a group 1 element reacts with water
Why is the final solution alkaline when a group 1 element reacts with water?
Due to the formation of the soluble OH
What happens to lithium when reacted with water?
Reacts least vigorously and doesn’t melt
Which group 1 metal reacts least vigorously with water and doesn’t melt?
Lithium
How does sodium react with water?
Melts to form a silvery ball on the water’s surface and hisses as it moves on the surface of the water
Which element melts to form a silvery ball on water’s surface and hisses as it moves on the surface of water when it’s reacted with it?
Sodium
What does potassium do when reacted with water?
Catches fire and burns with a lilac flame
Which element catches fire and burns with a lilac flame when reacted with water?
Potassium
Write the equation for sodium (a group 1 metal) reacting with water
2Na + 2H20 —> 2NaOH + H2
Describe the reactivity of group 2 elements
Less reactive than group 1 elements
What happens when magnesium reacts with cold water?
Reacts very slowly (takes many weeks to collect a sample of hydrogen gas)
A white suspension of magnesium hydroxide forms
Which group 2 element reacts very slowly with water and takes many weeks to generate a sample of hydrogen gas?
Magnesium
HOW slowly does magnesium react with water?
Takes many weeks to collect a sample of hydrogen gas
How do group 2 elements react with water?
Readily (apart from magnesium)
What’s the only group 2 element that doesn’t react readily with water?
Magnesium
What do group 2 elements do when reacted with water?
Sink (denser than group 1 metals)
Do not melt (high melting points)
Dissolve to leave a solution that’s slightly milky due to the hydroxide forming and bubbles due to the hydrogen gas released
Which group of metals - 1 or 2 - sink in water and why?
Group 2 as they’re denser
Why do group 2 elements not melt in water?
Have high melting points
What can we see when a a group 2 metal is reacted with water and why?
Metal dissolves to leave a solution that’s slightly milky due to the hydroxide forming
Bubbles as hydrogen gas is released
What type of reaction occurs with magnesium and steam?
Violent reaction
Which element has a violent reaction with steam?
Magnesium
What happens when magnesium reacts with steam?
Magnesium OXIDE and hydrogen form
Magnesium burns with a brilliant flame
When does magnesium form magnesium OXIDE and hydrogen and burn with a brilliant flame?
When reacted with steam
Brilliant flame
Very bright
Very bright flame
Brilliant flame
Equation for the reaction of magnesium with steam
Mg + H20(g) —> MgO + H2
Equation for magnesium with cold water
Mg + 2H20 —> Mg(OH)2 + H2
Describe the reaction between group 1 elements and oxygen
Combine spontaneously
What do group 1 elements do when reacted with oxygen? What must we do as a result of this?
Combine spontaneously
Stored under oil
Why are group 1 elements stored under oil?
Combine spontaneously with oxygen
What happens when a group 1 element is reacted with oxygen?
Burn vigorously to form an oxide which is a white solid
What is the oxide formed when group 1 elements react with oxygen?
A white solid
Equation for reaction between sodium and oxygen
4Na + 02 —> 2Na20
What happens to group 2 elements when reacted with oxygen?
Burn fiercely to form an oxide (white solid)
What do both group 1 and 2 elements do when reacted with oxygen?
Burn fiercely to form an oxide (a white solid)
How does magnesium react with oxygen?
Burns with a brilliant flame
Which group 2 element burns with a brilliant flame in oxygen?
Magnesium
Equation for the reaction between magnesium and oxygen
2Mg + 02 —> 2MgO
How do group 1 and 2 elements react with acid?
The reaction is too vigorous to carry out with metals apart or magnesium
Which metal is the only one that doesn’t react too vigorously with acids in order to be done?
Magnesium
Describe the reaction between magnesium and acids
-reacts quickly with dilute acids
-the mixture effervesces
-magnesium dissolves to leave a colourless solution
-exothermic
-hydrogen forms
What does a metal form when it reacts with an acid?
A salt and hydrogen
Equation for magnesium reacting with sulphuric acid
Mg + H2S04 —> MgS04 + H2
Equation for the reaction between magnesium and hydrochloric acid
Mg + 2HCl —> MgCl2 + H2
Equation for the reaction between magnesium and nitric acid
Mg + 2HNO3 —> Mg(N03)2 + H2
What is the test for hydrogen?
Burns wit a squeaky pop
Which gas burns with a squeaky pop?
Hydrogen
What reflects on how elements are stored?
Their reactivity
Which group 2 elements are stored without any specific precautions? Why?
Magnesium and calcium as they’re not as reactive as the other group 2 elements
How are magnesium and calcium stored?
Without any specific precautions
Which group 2 elements are stored under special precautions and what are these?
Strontium and barium - under oil
Which group 2 elements are stored under oil? Why?
Strontium and barium as they’re more reactive than magnesium and calcium
Which group’s elements are all stored under oil?
Group 1 elements
How are group 1 elements stored?
Under oil
What do group 1 and 2 elements all act as in their reactions and what happens to them?
Reducing agents and are oxidised (lose electrons)
Which elements always act as reducing agents in their reactions and what does this mean?
Group 1 and 2 elements - they’re oxidised (i.e - they lose electrons)
Equation to show calcium being oxidised (as it’s a reducing agent)
Ca —> Ca2+ + 2e-
Why are group 1 and 2 elements described as mainly ionic?
They lose electrons readily to form cations
Do elements in group 1 and 2 lose electrons readily? What does this allow them to do?
Yes, to form cations
So, they’re mainly ionic
What are the oxides and hydroxides and why?
Strong bases as they are ionic compounds
What does the fact that group 1 and 2 elements are ionic compounds make them?
Strong bases
Sodium oxide formula
Na20
Sodium hydroxide formula
NaOH
Calcium oxide formula
CaO
Calcium hydroxide formula
Ca(OH)2
What’s the oxidation state of sodium in sodium hydroxide?
+1
What’s the oxidation state of sodium in sodium oxide?
+1
What’s the oxidation state of calcium in calcium hydroxide?
+2
Whats the oxidation state of calcium in calcium oxide?
+2
Na20
Sodium oxide
What are group 1 oxides?
Basic oxides
What do group 1 oxides do in water?
Dissolve readily to give strongly alkaline solutions containing hydroxide ions
What oxides dissolve the most readily in water - group 1 or 2?
Group 1
