Bonding- should do extra practice qs Flashcards
How are ions formed?
- In an atom the number of electrons is equal to the number of protons so the atoms are neutral (they have no overall charge)
- when atoms lose or gain electrons they become ions
- metal atoms usually lose electrons to form positive ions (cations), this is called oxidation
- non-metal atoms usually gain electrons to form negative ions (anions), this is called reduction.
What does an atom which loses 2 electrons have a charge of?
2+
What does an atom which gains 2 electrons have a charge of?
2-
What are giant ionic structures?
- Ionic, giant covalent and metallic bonding products have giant structures made up of oppositely charged ions
- the ions are arranged in a regular three-dimensional giant lattice structure with alternating positive and negative ions
- the ions are held together by very strong electrostatic forces of attraction in all directions
What type of bonding involves a metal and non metal?
Giant ionic bonding
What are the properties of ionic compounds?
HIGH MELTING AND BOILING POINTS
-a lot of energy is needed to overcome the strong electrostatic attractions between the oppositely charged irons in the giant lattice.
-The higher the charges on the ions the stronger the electrostatic attractions so the higher the melting and boiling points
-for example MGO has a higher melting point than NaCl
DONT CONDUCT ELECTRICITY IN SOLID STATE
-This is because the ions are in fixed positions and cannot move
-however they will conduct electricity when melted (molten) or in solution (dissolved in the water) because the ions are free to move and carry the charge
BRITTLE
-The crystals can be split if force is applied as ions of the same charge come into contact and repel each other
- ionic compounds are often soluble in water as the polar water molecules are able to attract the irons and pull them out of the lattice
What is the order of the charges of the different elements in each of the different groups (1-7)
1+,2+,3+(group 3), 2+,3-,2-,1-
What type of bonding involves only non metals?
Covalent bonding
What type of bonding involves only metals?
Giant metallic bonding
What are the two types of structures of covalent bonding?
Giant (e.g diamond)and simple molecular
What particles does giant covalent bonding use?
Carbon atoms
What particles does simple molecular covalent bonding use?
Molecules
What forces does giant covalent bonding use?
Covalent bonds
What forces does simple molecular bonding use?
Intermolecular forces
Is the melting point of giant covalent bonding high or low?
High because of the strong covalent bonds