Davies Exam Flashcards
The two leftmost columns make up the …
This is called the … because elements in it have all their valence electrons in s orbitals.
Note, Helium is also an s block element because it has the electron configuration __
The two leftmost columns make up the s block.
This is called the s block because elements in it have all their valence electrons in s orbitals.
Note, Helium is also an s block element because it has the electron configuration 1s2.
The six rightmost columns make up the ___
This is called the p block because elements in the p block have a partially filled p sub-shells
The six rightmost columns make up the p block.
This is called the p block because elements in the p block have a partially filled p sub-shell.
The d block lies …
Elements in the d block have a …
Elements in the d block are often called ____
The d block lies between the s and p blocks.
Elements in the d block have a partially filled d sub-shell.
Elements in the d block are often called transition metals.
Atomic radius ___ along a period.
This is because …
As you add protons, you also add ___. But these are all being added to the same shell, so this does not affect the …
So each electron ____
Atomic radius decreases along a period.
This is because the number of protons in the nucleus increases across the period.
As you add protons, you also add electrons. But these are all being added to the same shell, so this does not affect the radius.
So each electron feels a stronger attraction to the nucleus and is held closer.
In Period 3, sulfur has a smaller atomic radius than phosphorus
Sulfur has one more electron but still only fills up the same shell (3p) as phosphorus, so the radius is not affected.
But sulfur has one more proton than phosphorus - this does affect …
___ has a greater nuclear charge because of …
This pulls …
This means the …
In Period 3, sulfur has a smaller atomic radius than phosphorus.
Sulfur has one more electron but still only fills up the same shell (3p) as phosphorus, so the radius is not affected.
But sulfur has one more proton than phosphorus - this does affect the radius.
Sulfur has a greater nuclear charge because of having more protons.
This pulls the electrons closer.
This means the atomic radius is smaller.
Ionisation energy ___ along a period.
This is because the …
The attraction increases because the …
Ionisation energy increases along a period.
This is because the electrostatic attraction of each electron to the nucleus increases.
The attraction increases because the proton number increases.
In Period 3, chlorine has a greater nuclear charge than sulfur because …
So the electrostatic charge between electrons and the nucleus in chlorine will be ___
So the … is greater
In Period 3, chlorine has a greater nuclear charge than sulfur because it has a greater proton number.
So the electrostatic charge between electrons and the nucleus in chlorine will be greater.
So the ionisation energy is greater.
… decreases down a group.
This is because the …
The electrostatic attraction of …
Ionisation energy decreases down a group.
This is because the outer electron is further from the nucleus down the group.
The electrostatic attraction of the outer electron to the nucleus decreases down the group.
In Group 2, magnesium is below beryllium.
Magnesium fills up an extra electron shell than beryllium.
This means an electron is further from the nucleus in magnesium and so …
So the … of magnesium is lower than beryllium.
In Group 2, magnesium is below beryllium.
Magnesium fills up an extra electron shell than beryllium.
This means an electron is further from the nucleus in magnesium and so the electrostatic attraction is less.
So the ionisation energy of magnesium is lower than beryllium.
Across a period:
1 The ... increases 2 So the ... increases 3 ... between electrons and nucleus 4 Requires more energy to ...
Across a period:
1 The proton number increases 2 So the nuclear charge increases 3 Greater electrostatic attraction between electrons and nucleus 4 Requires more energy to remove an electron
The periodic atomic radii trend is that the atomic radius will …
The periodic atomic radii trend is that the atomic radius will decrease across a period.
Structure on mpt
For metals:
The greater the … the greater the melting point.
For covalent compounds:
Molecular solids have ___ melting points.
Giant covalent structures have relatively ___ melting points.
Structure on mpt
For metals:
The greater the number of valence electrons, the greater the melting point.
For covalent compounds:
Molecular solids have low melting points.
Giant covalent structures have relatively high melting points.
As you move along a period, you go from metals to giant covalent structures, to molecular solids.
The melting pints …
We will look at Period 3 to showcase this trend.
As you move along a period, you go from metals to giant covalent structures, to molecular solids.
Using our knowledge of melting points of different structures from the previous slide:
The melting points increase, peak sharply, and then decrease.
We will look at Period 3 to showcase this trend.
Na, Mg Al all have ___ structures.
… increase from Na to Al.
This is because each …
The … are greater, so …
Na, Mg Al all have metallic structures.
Melting point and boiling point increase from Na to Al.
This is because each element donates one more electron to the sea of free electrons.
The electrostatic attractions are greater, so the melting point rises.
Silicon has the highest ___
This is because …
To melt silicon, you must … and this …
Silicon has the highest melting point.
This is because it has a giant covalent structure.
To melt silicon, you must break strong covalent bonds, which requires a lot of energy.
P, S, Cl, Ar
These elements are …
They are held together by …
Sulfur has the highest melting point of the four because …
This means it has a lot of … so has …
By contrast, P exists as __ and Cl exists as __.
P, S, Cl, Ar
These elements are simple molecules.
They are held together by Van der Waals forces.
Sulfur has the highest melting point of the four because it exists as molecules of S8.
This means it has a lot of electrons per molecule, so has stronger Van der Waals attractions.
By contrast, P exists as P4 and Cl exists as Cl2.
Period 3
-
-
Period 3
Na, Mg, Al
Metallic
Si
Giant covalent
Highest melting point
P, S, Cl
Molecular solid
Ar
Atomic solid
Lowest melting point
Why does the distance between electrons and nuclei increase down a group?
Why does the distance between electrons and nuclei increase down a group?
Valence electron shell gets bigger
Metallic Melting Points
Aluminium has a higher melting point than sodium because … This …
Metallic Melting Points
Aluminium has a higher melting point than sodium because it donates more electrons into the sea of free electrons. This increases the strength of electrostatic attractions.
What happens to atomic radius across a period?
What happens to atomic radius across a period?
Decreases
What happens to the atomic radius as you move up the group?
What happens to the atomic radius as you move up the group?
Decreases
Which of the following has the lowest boiling point?
Mg
Na
Al
Which of the following has the lowest boiling point?
Na
Which of the following has the highest melting point?
P
S
Cl
Which of the following has the highest melting point?
S
Below shows the ionisation energies of an atom.
First: 419 Second: 3051 Third: 4419 Fourth:5878 Fifth: 7975 Sixth: 9594
What group is this atom in?
Below shows the ionisation energies of an atom.
First: 419 Second: 3051 Third: 4419 Fourth:5878 Fifth: 7975 Sixth: 9594
What group is this atom in?
Group 1
Which of the following has the highest first ionisation energy?
Mg
Al
Na
Which of the following has the highest first ionisation energy?
Mg
Properties of Group 2 Metals
___ in the same group have similar properties. Here, we shall look at the similarities between the properties of the Group 2 elements.
Atomic radius and ionisation energy What increases as you go down Group 2? And why? What decreases as you go down Group 2. Why?
Properties of Group 2 Metals
Elements in the same group have similar properties. Here, we shall look at the similarities between the properties of the Group 2 elements.
Atomic radius and ionisation energy
Atomic radius increases as you go down Group 2.
This is because each extra electron shell is further away.
Ionisation energy decreases as you go down Group 2.
This is because the outer electrons are further away and experience less attraction to the nucleus.
Melting point
What decrease as you go down Group 2. And why? The free electrons ... ... is weaker, so the melting point is lower Magnesium has an anomalously ... This is because ...
Melting point
Melting points decrease as you go down Group 2.
This is because the ion cores have larger radii down the group.
The free electrons experience less attraction to the nuclei because of the larger radii.
The bonding is weaker, so the melting point is lower.
Magnesium has an anomalously low melting point.
This is because it has a different crystal structure to the rest of Group 2.
Reactions with water
Group 2 metals react with water to form ___. For example:
Mg + 2H2O → ___
___ increases as you go down Group 2. This is because …
Beryllium is an exception. If beryllium were to lose two electrons it would … This would make it…and so …
Reactions with water
Group 2 metals react with water to form metal hydroxides. For example:
Mg + 2H2O → Mg(OH)2 + H2
Reactivity increases as you go down Group 2. This is because the lower elements have lower ionisation energies.
Beryllium is an exception. If beryllium were to lose two electrons it would be tiny and have a very high charge density. This would make it unstable and so beryllium doesn’t react with water.
Solubility of salts
The solubility of hydroxides increases as you go down Group 2.
Magnesium hydroxide is very insoluble. The phrase to use for this is ‘sparingly soluble’.
The solubility of sulfates decreases as you go down Group 2.
Barium sulfate is completely insoluble.
Solubility of salts
The solubility of hydroxides increases as you go down Group 2.
Magnesium hydroxide is very insoluble. The phrase to use for this is ‘sparingly soluble’.
The solubility of sulfates decreases as you go down Group 2.
Barium sulfate is completely insoluble.
