Covalent and Ionic Bonding Overview

Covalent Bonding

• Occurs between two non-metal atoms
• A shared pair of electrons forms a covalent bond
• Eight diatomic elements held by covalent bonding: Hydrogen (H₂), Oxygen (O₂), Nitrogen (N₂), and the Group 7 elements (Halogens)
• Molecular compounds (e.g., water (H₂O), ammonia (NH₃), methane (CH₄)) have specific shapes due to covalent bonds
• Covalent molecular substances have low melting and boiling points due to weak bonds between molecules
• Covalent network substances (e.g., diamond, graphite, silicon dioxide) have high melting and boiling points due to strong covalent bonds
• These strong covalent bonds hold atoms tightly together

Ionic Bonding

• Occurs between a metal and a non-metal atom
• Forms charged particles called ions
• Metal loses outer electrons to become a positive ion
• Non-metal gains electrons to become a negative ion
• Electrostatic forces hold the oppositely charged ions strongly together in a lattice structure
• Ionic compounds have high melting and boiling points

Solubility

• "Like dissolves like" - ionic compounds dissolve in polar solvents, like water
• Covalent compounds dissolve in covalent solvents, like hexane

Electrical Conductivity

• Metals conduct electricity when solid or liquid due to free-moving electrons
• Covalent compounds do not conduct electricity
• Ionic compounds only conduct electricity when molten (liquid) or in solution due to ions being free to move

Metallic Bonding

• Found in metal elements
• Atoms lose outer electrons which become delocalized (free-moving) and form a 'sea' of electrons
• Free movement of electrons allows for electrical conductivity in metals

Chemical Symbols & Formulae

• Elements have one capital letter symbol
• Compounds are named using elements from the periodic table
• The second element's suffix becomes '-ide' (e.g. in NaCl) for two elements
• The second name in compounds containing oxygen ends in '-ate', and oxygen is excluded from the name (e.g. copper sulphate).
• Valences are numbers of bonds to create compounds
• Formulas show numbers of elements present in compound

Chemical Equations

• Reactants and products are represented with words
• Chemical formulas are used in chemical equations (e.g., hydrogen + oxygen --> water => H₂ + O₂ --> H₂O)

Formula Mass

• Sum of relative atomic masses (RAMs) of atoms in a molecule's formula. (e.g. Determine formula mass for H₂O: 2(H) + 1(O) = (2 x 1) + (16) = 18 amu)

This quiz covers the fundamental concepts of covalent and ionic bonding. It explores how these types of bonds form between non-metals and metals and the properties of the resulting compounds. Understand the differences in bonding strength and the implications for melting and boiling points.