Week 3

Explain the difference between ionic and covalent bonding

Ionic occurs between nonmetals and metals, involving transfer of electrons, while covalent bonding occurs between nonmetals through the sharing of electrons. Ionic bonds create charged ions, whereas covalent bonds result in neutral molecules.

Explain the difference between a bond pair and lone pair of electrons

A bond pair of electrons is shared between two atoms, forming a covalent bond, while a lone pair of electrons is a pair of valence electrons that are not shared with another atom.

Describe how polyatomic ions represent two or more covalently bonded atoms which have an overall charge

Polyatomic ions consist of groups of atoms bonded together covalently, carrying a net positive or negative charge due to an imbalance of protons and electrons. If it has a negative charge, it usually has one less bond than usual for the valence of its atoms, if positive it has one more.

Explain the difference between molecular and network solids

Molecular solids consist of molecules held together by intermolecular forces, while network solids are composed of a continuous network of covalent bonds, resulting in much higher melting points and greater structural integrity.

Explain how an acid supplies H+ ions and exists in water

An acid donates hydrogen ions (H+) when dissolved in water, increasing the concentration of H+ in the solution. The actual H+ ion does not exist itself for very long, attaching to the water to from a H3O+ ion. This process typically leads to a decrease in pH and indicates the acidic nature of the solution.

Explain that the mass reported is a weighted average of the mass of the individual isotopes of an element

Explain the difference between atomic mass and molar mass

Atomic mass is the mass of a single atom of an element, measured in atomic mass units (amu), while molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol).

Convert between mass, moles, and number of atoms/ions/molecules

Compare the properties of molecular vs network solids

Molecular materials are soft when solid with a low melting point (wax), and may also be gases or liquids at room temperature. Network materials are hard solids with high melting points. Hence, covalent bonds are broken when solid melts.

Explain the wave theory and homonucleaer covalent bond formation

Wave theory describes covalent bond formation occuring when the wave functions of neighbouring atoms are in phase with one another, causing constructive interference. The resulting wave/molecular orbital increases, hence the electron density between the two atoms increases. This increased density between the two atoms stabilizes the bond, leading to the formation of a stable molecule.

Chemical reactions occur because:

reactants collide with sufficient energy and proper orientation to form products, driven by changes in enthalpy and entropy. Products contain less energy than reactants and systems go to lowest energy state (burning gases). OR energy supplied to force reactants to products which have higher energy (blast furnace).