Bonding and properties of materials Flashcards
What is a covalent bond?
A covalent bond is a shared pair of electrons between atoms of two nonmetal elements.
Why do covalent bonds happen?
The positive nuclei from two atoms are held together by the attraction to the shared pair of electrons between them. Covalent bonds are strong bonds.
Properties of covalent molecular bonds? (Melting point, state and conductivity)
Covalent Molecules have low melting and boiling points, are liquid or gas at room temperature and never Conduct electricity.
What’s a diatomic molecule?
Molecule that contains only two atoms (gen-u-ine)
Properties of a covalent network?
They are solids with high melting points and are much larger molecules for example diamond and graphite or covalent networks. They never conduct electricity except graphite.
What is ionic lattice bonding?
Ionic lattice bonds is the electrostatic force of attraction between a positively charged metal ion and a negatively charged nonmetal ion.
What is Metallic bonding?
The electrostatic force of attraction between positively charged metal ions and negatively charged delocalised electrons.
What is electrolysis?
Electrolysis is the breaking up of an ion solution using electricity.
Why is a D.C. current needed for electrolysis?
A direct current power supply must be used so there is an obvious positive and negative electrode so the products of electrolysis can be identified.
Properties of a ionic lattice? (Melting point, state and conductivity)
Ionic lattices have high melting and boiling points, are solid and only conduct electricity when molten or in solution.
Properties of metallic bonding? (Melting point, state and conductivity)
Metallic bonds have high melting points are solid except from mercury and conduct electricity.
Why do ionic compounds conduct electricity when molten?
Because their ions are free to move
What are covalent molecules?
Atoms that share pairs of electrons form molecules. A molecule is a group of atoms held together by covalent bonds.
What is a Covalent network?
A covalent network structure consists of A giant three-dimensional lattice of covalently bonded atoms.
Why can metallic substances conduct electricity?
Free moving electrons
