TOPIC 2 - BONDING AND STRUCTURE Flashcards
What is an ionic bond?
The electrostatic force of attraction between oppositely charged ions
What is a covalent bond?
The electrostatic attraction between the nuclei of two atoms and the bonding electrons of their outer shell
How does ionic charge affect ionic bonding?
The greater the charge on an ion, the stronger the ionic bond
How does ionic bond strength affect melting/boiling points?
The higher the ionic bond strength the higher melting/boiling points.
How does ionic radii affect ionic bonding?
The smaller the ionic radii the stronger the ionic bond, as electrostatic attraction gets weaker with distance, so small, closely packed ions have stronger ionic bonding
What happens to ionic radius as you go down a group?
It increases
What are isoelectronic ions?
Isoelectronic ions are ions of different atoms with the same number of electrons
Why do giant ionic lattice structures form?
They form because each ion is electrostatically attracted in all directions to ions of the opposite charge
How does bond length affect bond enthalpy in a covalent bond?
The shorter the bond length the higher the bond enthalpy
What is a dative (coordinate) covalent bond?
A covalent bond where both electrons come from one atom
How many BP and LP and bond angle for a linear molecule?
2 BP, 0 LP, 180
How many BP and LP and bond angle for a trigonal planar molecule?
3 BP, 0 LP, 120
How many BP and LP and bond angle for a tetrahedral molecule?
4 BP, 0 LP, 109.5
How many BP and LP and bond angle for a trigonal bipyramidal molecule?
5 BP, 0 LP, 90 and 120
How many BP and LP and bond angle for an octahedral molecule?
6 BP, 0 LP, 90
How many BP and LP and bond angle for a trigonal pyramidal molecule?
3 BP, 1 LP, 107
How many BP and LP and bond angle for a V shaped (bent) molecule?
2 BP, 2 LP, 104.5
What properties do giant covalent structures have?
High melting points, hard, good thermal conductors, insoluble, can’t conduct electricity
Which one giant covalent structure can conduct electricity?
Graphite, as the carbon atoms form sheets leaving a free 4th outer electron free to move
What is electronegativity?
Electronegativity is the ability of an atom to attract the bonding electrons in a covalent bond
What happens when a bond is between two atoms with different electronegativities?
The bonding electrons will be pulled towards the more electronegative atom, which causes the electrons to be spread unevenly, and so there will be a charge across the bond, and the bond is said to be polar
