4.1 Ionic Bonding And Structure Flashcards
What are the outer most electrons of an atom called?
Valence electrons
How does an atom change when it forms an ionic bond?
The becomes an ion with an overall charge because it’s gained or lost and electron
What is a cation?
An atom which has lost an electron from its outer shell and become a positive ion
What is an anion?
An atom which has gained electrons in its outer shell in order to form a negative ion
Give examples of polyatomic ions!
Nitrate Hydroxide Hydrogen carbonate Carbonate Sulphate Phosphate Ammonium
Electrons from the …….. Tend to be transferred To the ……….
Electrons from the metal tend to be transferred to the non metal
What is an ionic bond?
The electrostatic attraction between two oppositely charged ions (neutral compound)
What structure do ionic compounds have?
Lattice structure because the electrostatic attraction causes the ions to surround themselves with the oppositely charged ions forming a 3D CRYSTALLINE STRUCTURE
What is lattice energy?
A measure of the strength of attraction between the ions with in a lattice
What kind of boiling and melting points do ionic compounds tend to have?
High melting and boiling points because the electrostatic attractions are very strong, therefore require a large amount of energy to break
What is coordination number?
The number of ions that surround one ion within a lattice
Do ionic compounds have a low or high volatility?
Low
Are ionic compounds soluble?
They are generally soluble in ionic or polar solvents but are insoluble in non-polar solvents
What happens when an ionic compound is added to water?
The partial charges of the hydrogen and oxygen in the water molecules will be attracted to the ion of the opposite charge. This pulls the ions away and separates them from the lattice and the ions become surrounded by water molecules a.k.a hydrated
Can ionic compounds carry charge in the solid state?
No because there are no delocalised ions which can carry charge through the compound
Can ionic compounds carry charge in the liquid or aqueous state?
Yes because the ions are able to move around and therefore carry an electrical charge through the substance
How can we predict the tendency of an ionic bond?
Looking at the electro-negativity values and seeing if there is a large difference between them. If so the electrons will be pulled more towards one atom giving it full control of the electrons making it an ionic bond.
Why are ionic compounds brittle?
Because the movement is forcing charged ions against each other which increases the repulsion between the positive nuclei’s and causes the substance to split.
Explain what happens to the electron configurations of Mg and Br when they react to form the compound magnesium bromide
The magnesium atom loses two electrons from its 3s orbital and the two bromine atoms gain one electron into their 4p sub shell. These two ions then attract each other by electrostatic forces and form a lattice.
Which fluoride is the most ionic?
NaF. CsF. MgF2. BaF2.
CsF because it has the greatest difference in electronegativity values
How could you test if something was an ionic compound?
Test its:
Melting point - would be very high
Solubility - dissolve in polar substances
Conductivity - they are good conductors in aqueous solutions
What charge do all atoms have? And why?
Neutral, because the protons and electrons cancel their +1 charges out and the neutrons have no charge
