Structure and Bonding 1 - Types of Bonding Flashcards
what do atoms want to achieve when bonding and why?
a full outer shell, in order to achieve a noble gas configuration, (most stable)
how is an ionic bond formed?
a metal transferring electrons to a non-metal
define ionic bond
the bond that is caused by the electrostatic attraction between a positively charged ions (cations) and a negatively charged ions (anions) in a lattice
give the charge on a sulphate ion
SO4 2-
give the charge on a hydroxide ion
OH -
give the charge on a nitrate ion
NO3 -
give the charge on a carbonate ion
CO3 2-
give the charge on an ammonium ion
NH4 +
how do you tell the charge of an ion using the periodic table?
group 1 = +1
group 2 = +2
group 7 = -1
group 6 = -2 etc
which 2 factors affect the strength of an ionic bond? what can these be refered to as together?
the size of ions and the magnitude of charge on ions, can be taken together as SURFACE CHARGE DENSITY, charge / SA
how does the size of an ion affect the strength of an ionic bond?
charges closer together will form stronger electrostatic forces
how does the magnitude of charge on an ion affect the strength of an ionic bond?
ions with higher charged will form stronger electrostatic forces
describe the structure of an ionic crystal
a giant crystalline lattice composed of repeating positive and negative ions
explain what the coordination number in NaCl is a why?
coordination number = 6
because in the 3D lattice each Na+ is in contact with 6Cl-
describe the position and movement of ions in a solid ionic compound.
what happens when a solid ionic compound is heated?
in a solid ionic compound the IONS are not free to move, and vibrate about a fixed position.
when a solid ionic compound is heated the ions vibrate more strongly, and are free to move
state the 4 properties of ionic compounds
1) high melting points
2) don’t conduct when solid
3) conduct when molten or aqueous
4) often water soluble
explain why ionic compounds have high melting points
the strong electrostatic forces of attraction between oppositely charged ions requires a lot of energy to overcome
explain why ionic compounds don’t conduct electricity when solid
the ions are about fixed positions throughout the lattice and so cannot move or carry charge
explain why ionic compounds conduct electricity when molten or aqueous
ions are free to move and carry charge throughout the structure