1. a) Valency refers to the combining capacity of an element, which is determined by the number of electrons it needs to gain, lose or share in order to achieve a full outer shell. Oxidation number, on the other hand, is the charge that an atom would have if the shared electrons were divided equally between the atoms in a compound.
b) Valency and oxidation numbers of the elements:
- Na: Valency 1, Oxidation number +1
- Mg: Valency 2, Oxidation number +2
- Ba: Valency 2, Oxidation number +2
- Co: Valency 2, Oxidation number +2
- Ni: Valency 2, Oxidation number +2
- S: Valency 2, Oxidation number -2
- C: Valency 4, Oxidation number +4
- Si: Valency 4, Oxidation number +4
- Cl: Valency 1, Oxidation number -1
- Al: Valency 3, Oxidation number +3
2. Electronegativity, first ionization energy, and standard electrode potential contribute to bonding by determining how likely an atom is to attract or lose electrons in a chemical reaction. Electronegativity affects the type of bonding that occurs, with a large electronegativity difference leading to ionic bonding, while a small difference leads to covalent bonding. First ionization energy determines how easily an atom can lose an electron to form a positively charged ion, while standard electrode potential measures the ability of an atom to attract electrons in a chemical reaction.
3. Types of bonding:
- Ionic bonding: Involves the transfer of electrons from one atom to another, creating ions with opposite charges that attract each other (e.g. NaCl).
- Covalent bonding: Involves the sharing of electrons between atoms to achieve a full outer shell (e.g. H2O).
- Metallic bonding: Involves the delocalization of electrons within a metal lattice, creating a "sea" of electrons that hold the metal atoms together (e.g. copper).
- Van der Waals force: Weak intermolecular forces that hold molecules together, including London dispersion forces, dipole-dipole interactions, and hydrogen bonding (e.g. between noble gases).
- Hydrogen bonding: A specific type of dipole-dipole interaction where a hydrogen atom is covalently bonded to a highly electronegative atom (e.g. H2O).
4. Minerals are naturally occurring inorganic solids with a definite chemical composition and a crystal structure. Examples of minerals formed through:
- Ionic bonding: Halite (NaCl)
- Covalent bonding: Diamond (C)
5. Silica is important in the earth's crust because it is one of the most abundant minerals and plays a crucial role in the formation of rocks and minerals. Common groups of silicate minerals include:
- Nesosilicates: Composed of isolated silicate tetrahedra (e.g. olivine)
- Sorosilicates: Composed of pairs of silicate tetrahedra sharing oxygen atoms (e.g. epidote)
- Cyclosilicates: Composed of rings of silicate tetrahedra (e.g. beryl)
- Inosilicates: Composed of chains of silicate tetrahedra (e.g. pyroxene)
- Phyllosilicates: Composed of sheets of silicate tetrahedra (e.g. mica)
- Tectosilicates: Composed of a three-dimensional network of silicate tetrahedra (e.g. quartz)
1. a)Differentiate between valency and oxidation number
b)Write the valency and oxidation numbers of the following elements: Na, Mg, Ba,
Co, Ni, S, C, Si, Cl, Al
2. State how electronegativity, first ionization energy and standard electrode potential
contribute to bonding.
3. Explain the types of bonding blow using examples
• Ionic bonding
• Covalent bonding
• Metallic bonding
• Van der waals force
• Hydrogen bonding
4. What are minerals and state examples of minerals formed through
• Ionic bonding
• Covalent bonding
5. Why is silica important when we talk about earth’s crust? Name the common groups of
silicate and briefly state their compositions.
1 answer