Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
29 Cards in this Set
- Front
- Back
|
Define the term ionic bonding |
The term ionic bonding is the strong electrostatic attraction between oppositely charged ions |
|
|
Describe the effects of the ionic radius and ionic charge on the strength of bonding |
🌟The smaller the ionic radius the stronger the bond 🐁🔴💪 Because electrostatic attraction gets weaker with distance🛣 🌟The greater the ionic charge the stronger the bond 🐘⚡️💪 |
|
|
Explain the reasons for the trends in ionic radii down |
🌟The ionic radius increases as you go down the group ★This is because extra electron shells are added ➕🐚 |
|
|
Explain the trends in ionic radius for a group of isoelectronic ions |
★Ionic radius decreases with increasing atomic number 🌟As you go down the series the number protons increases 🌟This means the electrons are more strongly attracted to the nucleus so will be pulled in closer ➕💕 |
|
|
Explain the physical properties of ionic compounds |
🌟High melting point🌡🗻 ★Lots of energy is required to overcome the combined electrostatic attraction of all the ions in the giant lattice network 🌟Brittleness💔 ★ When stress is applied oppositely charged layers slide past one another and repel eachother. 🌟Electrical conductivity⚡️ ★Charged particles migrate to oppositely charged electrodes when molten or aqueous 🌟Solubility🍷 ★They're mostly soluble as the ions can be pulled apart by polar molecules such as water
|
|
|
How do the physical properties of ionic compounds provide evidence for the theory of ionic bonding |
🌟High Melting point 🗻🌡 ★Shows ions are held together by strong attraction. Possitive and negative ions are strongly attracted to eacother 🗼 🌟Solubility🍷 ★Lattice pulled apart by polar molecules such as water and not non polar molecules--- so particles must be charged ➕/➖ 🌟Not conducting electricity when solid ⚡️🚫♦ ★Supports the ideas the the ions are held in fixed positions by strong ionic bonds when solid, but free to move when liquid/aqueous🔧 🌟Their brittleness ★When shaped like charged ions are directly above each other. There repulsion is very strong causing it to break. ★This supports the idea of a lattice structure |
|
|
Explain how the migration of ions provides evidence for the presence of charged particles. |
🌟 Using the example of green copper (II) chromate (IV) solution 💚 🌟Copper (II) ions are blue in solution💙 🌟Chromate (IV) ions are yellow in solution 💛 💙When you pass a current through the cations migrate to the cathode 💛And the anions migrate to the anode |
|
|
Define the term covalent bond |
🌟 A covalent bond is the strong electrostatic attraction between two possitive nuclei and the shared electrons in the bond |
|
|
Draw the dot and cross diagram for XeF₄ |
|
|
|
Explain the relationship between the bond length and bond strength in covalent bonds |
🌟A greater bond strength results in… 🌟Shorter bond length. Because nuclei are pulled closer together. ★Bonds increase in strength when there is an increase in electron density (i.e. more electrons in the bond) |
|
|
Draw the dot and cross diagram for carbon monoxide CO |
There is are two covalent bonds and one dative |
|
|
Explain how the shape of a molecules is determined |
🌟Electron pairs will arrange themselves around the central molecule 🌟So that repulsion is minimised 😷🐁 |
|
|
Which pairings of bond pairs have the greatest repulsion |
1⃣️Lone pair-Lone pair 2⃣️Lone pair-Bond pair 3⃣️Bond pair-Bond pair ★The number of electron pairs and the number of bond pairs can be used to explain the shapes of molecules |
|
|
Define electronegativity |
🌟electronegativtiy is the ability of an atom to attract the bonding electrons in a covalent bond |
|
|
What causes polarity in bonds? |
🌟It is caused by a difference in electronegativity 🌟The electrons will be pulled towards more electronegative atom 🌟The electrons will be unevenly spread 🌟So there will be a charge across the bond |
|
|
Explain what a dipole is |
🌟A dipole is a difference in charge between two atoms 🌟Caused by a shift in electron density |
|
|
What causes bond polarity in molecules? |
🌟A difference in electronegativity shifts the electron density causing a charge across the bonds, a polar bond 🌟Dipoles are vectors 🌟So if the bonds all point in roughly same direction the molecule will be polar. |
|
|
Explain the scale from ionic to covalent in bonding |
🌟Only bonds between atoms of a single element can be purely ionic 🌟Similailry very few substances are completely ionic 🌟Most compounds are somewhere in the middle of these 2 extremes 🌟A higher difference in electronegativity indicates a more ionic character in bonding |
|
|
Explain what London Forces are |
🌟Electrons randomly move in the charge cloud↔️🌩 🌟At any point there could be a higher electron density on one side-- causing an instantaneous dipole💥 🌟This dipole can induce another istantaneous dipole on another atom. 🌟The two dipoles are then attracted to each other 💕 🌟Which induces another (i.e domino effect) ★Eventhough dipoles are constantly being created, destroyed and changed the overall effect is for the atoms to be attracted to eca |
|
|
Explain the forces of attraction between polar molecules |
🌟The δ⁻ and δ⁺ charges on the molecules cause weak of attraction to other molecules 🌟This is called a permanent dipole-permanent dipole bond 🌟This can happen in addition to London forces |
|
|
Explain what hydrogen bonding is |
🌟Hydrogen bonding is when hydrogen atoms in a covalent bond form partial bonds with lone pairs of electrons; 🌟Lone pairs of electrons belonging to the atom of another molecule ★This is becauee hydrogen hydrogen has a LOW CHARGE DENSITY ★So is highly polarised and attracted to the lone pairs
|
|
|
In which molecules does hydrogen bonding only occur |
Hydrogen bonded only occurs when hydrogen us bonded to: 🌟Flourine 🌟Nitrogen 🌟Oxygen ★Organic molecules containing -OH or -NH groups (i.e. Alcohols and Amines) |
|
|
Explain the trends in boiling temperatures of alkanes with longer chain lengths |
★Longer chain alknes have higher boiling points 🌟This is because they have larger electrons clouds 🌟Therefore there London forces will be stronger |
|
|
Explain the effect of branching in the carbon chain |
★Boiling point is higher in longer, non-branched, alkanes because: 🌟There are London forces between molecules, holding them together 🌟The longer the chain the stronger the London forces 🌟As Electrons interact at the points of contact 🌟and there are more points of contact (greater surface area) 🌟So more energy is required to overcome these forces.
|
|
|
Explain why alchols are less volatile than similairly sized alkanes |
🌟Alchols form hydrogen bonds 🌟Due to the δ⁺ of the hydrogen bond which is caused by the polar negative (-OH) group 🌟More energy is required to overcome these additional bonds. |
|
|
Explain the trend in the boiling points of hydrogen halides |
🌟HF forms hydrogen bonds 🌟Hydrogen bonding is the strongest intermolecular force so lots of energy is required to overcome them 🌟While in HCl to HI there is an increase in the number of electrons 🌟Resulting in greater London forces ★This overrides the effects of in the decrease of strength in permanent dipole-permanent dipole interactions 🇬🇧💪 |
|
|
Describe the factors that influence the choice of water as a solvent |
1⃣️Non polar substaces don't dissolve in water because they are not attracted to the δ⁻ of the -OH or the δ⁺ of the H 🌟So hydration does not occur 2⃣️Some ionic substance don't dissolve because their bonding between the in is two strong (e.g.) 3⃣️Halogenoalkanes contain non polar bonds but don't dissolve 🌟but their dipoles are too weak to form hydrogen bonds with water. 🌟And bonding in water is stronger than it would be with the halogenoalkanes. |
|
|
Explain metallic bonding |
🌟Metallic bonding is the strong electrostatic attraction between the nuclei of the metal cation and the delocalised electrons |
|
|
What type of structure is present in covalently bonded substances, ionic substances and solid metals. |
X |
