Topic 2- Bonding And Structure Flashcards
What is an ion?
A positively or negatively charged atom (or group of atoms)
How are ions made?
Via the gain or loss of electrons
What charge do cations and anions have?
Cation- positive
Anion- negative
Define an ionic bond
An ionic bond is the strong electrostatic attraction between 2 oppositely charged ions
What 2 things mainly affect ionic bonding?
Ionic Charge- the greater the charge of the ion, the greater the attraction, the stronger the bond.
Ionic radii- the smaller the radius of the ion, the closer they can pack together with other ions, electrostatic attraction diminishes with length so the closer the ion the stronger the bond.
What affects the atomic radius?
Ion charge- the greater the charge of the ion (positive) the stronger the attraction to the electrons- smaller radius as its pulled closer together
Electron shells-The ionic radius of a group decreases down a group as the charge is constant but thee number of electron shells increases- less attraction with distance
What is an isoelectronic ion?
Ions with the same number if electrons but different atoms.
What happens to the radius of isoelectronic ions as the atomic number increases?
It decreases
Why is it called a ‘giant’ ionic lattice?
Because it’s a lattice structure but the the same basic unit is repeated over and over again
What are the physical properties of ionic bonding?
They have high melting points- strong electrostatic forces of attraction between cation and anion.
Soluble in water (but not non polar solvents)- due to the uneven distribution of charge along a polar bond.
Don’t conduct electricity as a solid but do when molten
Cant be moulded/ reshaped- strong forces, no movement
They’re brittle
Define a covalent bond
The strong electrostatic forces of attraction between the positive nuclei of the 2+ atoms and the shared pairs of electrons in the bond.
If there are more electron pairs being shared then what happens to the strength of the covalent bond?
The bond strength increases & the bond length decreases as the forces of attraction increase as there is a greater negative charge to attract the positive nuclei of the atoms
